diff --git a/rsrc/graphicsUndithered/errors.png b/rsrc/graphicsUndithered/errors.png
new file mode 100644
index 00000000..fa5d2faf
Binary files /dev/null and b/rsrc/graphicsUndithered/errors.png differ
diff --git a/rsrc/graphicsUnditheredByHand/errors.png b/rsrc/graphicsUnditheredByHand/errors.png
new file mode 100644
index 00000000..fa5d2faf
Binary files /dev/null and b/rsrc/graphicsUnditheredByHand/errors.png differ
diff --git a/src/scenario/scenario.cpp b/src/scenario/scenario.cpp
index 772df0c0..037f1d2d 100644
--- a/src/scenario/scenario.cpp
+++ b/src/scenario/scenario.cpp
@@ -211,6 +211,26 @@ cScenario::cItemStorage::cItemStorage() : ter_type(-1), property(0) {
 		item_odds[i] = 0;
 }
 
+cTerrain const &cScenario::get_terrain(ter_num_t ter) const
+{
+	if (ter<ter_types.size())
+		return ter_types[ter];
+	static cTerrain badTerrain;
+	badTerrain.picture = -3;
+	badTerrain.map_pic = -3;
+	return badTerrain;
+}
+
+cTerrain &cScenario::get_terrain(ter_num_t ter)
+{
+	if (ter<ter_types.size())
+		return ter_types[ter];
+	static cTerrain badTerrain;
+	badTerrain.picture = -3;
+	badTerrain.map_pic = -3;
+	return badTerrain;
+}
+
 void cScenario::import_legacy(legacy::scenario_data_type const &old){
 	is_legacy = true;
 	difficulty = old.difficulty;
diff --git a/src/scenario/scenario.hpp b/src/scenario/scenario.hpp
index de9e395a..24d8531f 100644
--- a/src/scenario/scenario.hpp
+++ b/src/scenario/scenario.hpp
@@ -49,6 +49,8 @@ public:
 		cItemStorage& operator = (legacy::item_storage_shortcut_type const &old);
 	};
 	void destroy_terrain();
+	cTerrain const &get_terrain(ter_num_t ter) const;
+	cTerrain &get_terrain(ter_num_t ter);
 public:
 	unsigned short difficulty,intro_pic,default_ground;
 	int bg_out, bg_fight, bg_town, bg_dungeon;
diff --git a/src/scenario/terrain.cpp b/src/scenario/terrain.cpp
index e8a81f64..f38a18f3 100644
--- a/src/scenario/terrain.cpp
+++ b/src/scenario/terrain.cpp
@@ -421,7 +421,7 @@ cPictNum cTerrain::get_picture_num_for_terrain(pic_num_t bigPicture)
 				else             : PIC_CUSTOM_TER
 	 */
 	if(bigPicture < 0)
-		return cPictNum(-1,PIC_NONE);
+		return cPictNum(bigPicture,PIC_NONE);
 	if(bigPicture < 960)
 		return cPictNum(bigPicture,PIC_TER);
 	if(bigPicture < 1000)
diff --git a/src/scenedit/scen.actions.cpp b/src/scenedit/scen.actions.cpp
index 75936693..77ffdabb 100644
--- a/src/scenedit/scen.actions.cpp
+++ b/src/scenedit/scen.actions.cpp
@@ -794,7 +794,7 @@ static bool handle_terrain_action(location the_point, bool ctrl_hit) {
 						break;
 					case 0:
 						overall_mode = MODE_DRAWING;
-						set_string("Drawing mode",scenario.ter_types[current_terrain_type].name);
+						set_string("Drawing mode",scenario.get_terrain(current_terrain_type).name);
 						break;
 				}
 				break;
@@ -983,7 +983,7 @@ static bool handle_terrain_action(location the_point, bool ctrl_hit) {
 			{
 				auto& signs = editing_town ? town->sign_locs : current_terrain->sign_locs;
 				auto iter = std::find(signs.begin(), signs.end(), spot_hit);
-				short picture = scenario.ter_types[editing_town ? town->terrain(spot_hit.x,spot_hit.y) : current_terrain->terrain[spot_hit.x][spot_hit.y]].picture;
+				short picture = scenario.get_terrain(editing_town ? town->terrain(spot_hit.x,spot_hit.y) : current_terrain->terrain[spot_hit.x][spot_hit.y]).picture;
 				if(iter != signs.end()) {
 					edit_sign(*iter, iter - signs.begin(), picture);
 				} else {
@@ -1145,7 +1145,7 @@ static bool handle_terrain_action(location the_point, bool ctrl_hit) {
 				break; // Nothing to do here, of course.
 		}
 		if((overall_mode == MODE_DRAWING) && (old_mode != MODE_DRAWING))
-			set_string("Drawing mode",scenario.ter_types[current_terrain_type].name);
+			set_string("Drawing mode",scenario.get_terrain(current_terrain_type).name);
 		draw_terrain();
 		return true;
 	}
@@ -1228,10 +1228,10 @@ static bool handle_terpal_action(location cur_point, bool option_hit) {
 					else if(i == size_before) {
 						scenario.ter_types.resize(size_before + 16);
 						for(; i < scenario.ter_types.size(); i++)
-							scenario.ter_types[i].name = "New Terrain";
+							scenario.get_terrain(i).name = "New Terrain";
 					} else {
-						scenario.ter_types[i] = cTerrain();
-						scenario.ter_types[i].name = "Unused Terrain";
+						scenario.get_terrain(i) = cTerrain();
+						scenario.get_terrain(i).name = "Unused Terrain";
 					}
 				} else {
 					if(i == size_before) {
@@ -1262,27 +1262,28 @@ static bool handle_toolpal_action(location cur_point2) {
 				rectangle temp_rect = palette_buttons[i][j];
 				temp_rect.offset(RIGHT_AREA_UL_X + 5, RIGHT_AREA_UL_Y + terrain_rects[255].bottom + 5);
 				flash_rect(temp_rect);
+				auto const &ter_type=scenario.get_terrain(current_terrain_type);
 				switch(cur_palette_buttons[j][i]) {
 					case PAL_ARROW_UP: case PAL_ARROW_DOWN: // These two might never be used.
 					case PAL_BLANK: break;
 					case PAL_PENCIL:
-						set_string("Drawing mode",scenario.ter_types[current_terrain_type].name);
+						set_string("Drawing mode",ter_type.name);
 						overall_mode = MODE_DRAWING;
 						break;
 					case PAL_BRUSH_LG:
-						set_string("Paintbrush (large)",scenario.ter_types[current_terrain_type].name);
+						set_string("Paintbrush (large)",ter_type.name);
 						overall_mode = MODE_LARGE_PAINTBRUSH;
 						break;
 					case PAL_BRUSH_SM:
-						set_string("Paintbrush (small)",scenario.ter_types[current_terrain_type].name);
+						set_string("Paintbrush (small)",ter_type.name);
 						overall_mode = MODE_SMALL_PAINTBRUSH;
 						break;
 					case PAL_SPRAY_LG:
-						set_string("Spraycan (large)",scenario.ter_types[current_terrain_type].name);
+						set_string("Spraycan (large)",ter_type.name);
 						overall_mode = MODE_LARGE_SPRAYCAN;
 						break;
 					case PAL_SPRAY_SM:
-						set_string("Spraycan (small)",scenario.ter_types[current_terrain_type].name);
+						set_string("Spraycan (small)",ter_type.name);
 						overall_mode = MODE_SMALL_SPRAYCAN;
 						break;
 					case PAL_DROPPER:
@@ -1300,7 +1301,7 @@ static bool handle_toolpal_action(location cur_point2) {
 						break;
 					case PAL_BUCKET:
 						overall_mode = MODE_FLOOD_FILL;
-						set_string("Flood fill", scenario.ter_types[current_terrain_type].name);
+						set_string("Flood fill", ter_type.name);
 						break;
 					case PAL_ZOOM: // switch view
 						cur_viewing_mode = (cur_viewing_mode + 1) % 4;
@@ -1602,15 +1603,15 @@ void set_new_terrain(ter_num_t selected_terrain) {
 	if(selected_terrain >= scenario.ter_types.size()) return;
 	current_terrain_type = selected_terrain;
 	current_ground = scenario.get_ground_from_ter(selected_terrain);
-	cTerrain& ter = scenario.ter_types[current_terrain_type];
-	cTerrain& gter = scenario.ter_types[current_ground];
+	cTerrain const & ter = scenario.get_terrain(current_terrain_type);
+	cTerrain const &gter = scenario.get_terrain(current_ground);
 	if(gter.blockage >= eTerObstruct::BLOCK_MOVE || ter.trim_type == eTrimType::WALKWAY || /*current_ground == current_terrain_type ||*/
 	   (ter.trim_type >= eTrimType::S && ter.trim_type <= eTrimType::NW_INNER)) {
-		long trim = scenario.ter_types[current_ground].trim_ter;
+		long trim = gter.trim_ter;
 		if(trim < 0) current_ground = 0;
 		else current_ground = scenario.get_ter_from_ground(trim);
 	}
-	set_string(current_string[0],scenario.ter_types[current_terrain_type].name);
+	set_string(current_string[0],ter.name);
 }
 
 void handle_keystroke(sf::Event event) {
@@ -1870,7 +1871,7 @@ void unfrill_terrain() {
 	for(short i = 0; i < ((editing_town) ? town->max_dim : 48); i++)
 		for(short j = 0; j < ((editing_town) ? town->max_dim : 48); j++) {
 			terrain_type = editing_town ? town->terrain(i,j) : current_terrain->terrain[i][j];
-			cTerrain& ter = scenario.ter_types[terrain_type];
+			cTerrain const &ter = scenario.get_terrain(terrain_type);
 			
 			if(ter.frill_for >= 0)
 				terrain_type = ter.frill_for;
@@ -1896,21 +1897,19 @@ bool terrain_matches(unsigned char x, unsigned char y, ter_num_t ter) {
 	ter_num_t ter2;
 	if(editing_town) ter2 = town->terrain(x,y); else ter2 = current_terrain->terrain[x][y];
 	if(ter2 == ter) return true;
-	if(scenario.ter_types[ter2].ground_type != scenario.ter_types[ter].ground_type)
+	auto const &ter_type=scenario.get_terrain(ter);
+	auto const &ter_type2=scenario.get_terrain(ter2);
+	if(ter_type2.ground_type != ter_type.ground_type)
 		return false;
-	if(scenario.ter_types[ter].trim_type == eTrimType::NONE &&
-	   scenario.ter_types[ter2].trim_type >= eTrimType::S &&
-	   scenario.ter_types[ter2].trim_type <= eTrimType::NW_INNER)
+	if(ter_type.trim_type == eTrimType::NONE && ter_type2.trim_type >= eTrimType::S &&
+	   ter_type2.trim_type <= eTrimType::NW_INNER)
 		return ter == scenario.get_ground_from_ter(ter);
-	if(scenario.ter_types[ter2].trim_type == eTrimType::NONE &&
-	   scenario.ter_types[ter].trim_type >= eTrimType::S &&
-	   scenario.ter_types[ter].trim_type <= eTrimType::NW_INNER)
+	if(ter_type2.trim_type == eTrimType::NONE && ter_type.trim_type >= eTrimType::S &&
+	   ter_type.trim_type <= eTrimType::NW_INNER)
 		return ter2 == scenario.get_ground_from_ter(ter2);
-	if(scenario.ter_types[ter2].trim_type >= eTrimType::S &&
-	   scenario.ter_types[ter2].trim_type <= eTrimType::NW_INNER &&
-	   scenario.ter_types[ter].trim_type >= eTrimType::S &&
-	   scenario.ter_types[ter].trim_type <= eTrimType::NW_INNER)
-		return scenario.ter_types[ter].trim_type != scenario.ter_types[ter2].trim_type;
+	if(ter_type2.trim_type >= eTrimType::S && ter_type2.trim_type <= eTrimType::NW_INNER &&
+	   ter_type.trim_type >= eTrimType::S && ter_type.trim_type <= eTrimType::NW_INNER)
+		return ter_type.trim_type != ter_type2.trim_type;
 	return false;
 }
 
@@ -1932,10 +1931,11 @@ void set_terrain(location l,ter_num_t terrain_type) {
 	l2 = l;
 	
 	// Large objects (eg rubble)
-	if(scenario.ter_types[terrain_type].obj_num > 0){
-		int q = scenario.ter_types[terrain_type].obj_num;
-		location obj_loc = scenario.ter_types[terrain_type].obj_pos;
-		location obj_dim = scenario.ter_types[terrain_type].obj_size;
+	auto const &ter_type=scenario.get_terrain(terrain_type);
+	if(ter_type.obj_num > 0){
+		int q = ter_type.obj_num;
+		location obj_loc = ter_type.obj_pos;
+		location obj_dim = ter_type.obj_size;
 		while(obj_loc.x > 0) l2.x-- , obj_loc.x--;
 		while(obj_loc.y > 0) l2.y-- , obj_loc.y--;
 		for(short i = 0; i < obj_dim.x; i++)
@@ -1948,17 +1948,18 @@ void set_terrain(location l,ter_num_t terrain_type) {
 	
 	// First make sure surrounding spaces have the correct ground types.
 	// This should handle the case of placing hills around mountains.
-	unsigned int main_ground = scenario.ter_types[terrain_type].ground_type;
-	long trim_ground = scenario.ter_types[terrain_type].trim_ter;
+	auto const &terrain_ground=scenario.get_terrain(terrain_type);
+	unsigned int main_ground = terrain_ground.ground_type;
+	long trim_ground = terrain_ground.trim_ter;
 	for(int x = -1; x <= 1; x++) {
 		for(int y = -1; y <= 1; y++) {
 			location l3(l.x+x,l.y+y);
 			ter_num_t ter_there = editing_town ? town->terrain(l3.x,l3.y) : current_terrain->terrain[l3.x][l3.y];
-			unsigned int ground_there = scenario.ter_types[ter_there].ground_type;
+			unsigned int ground_there = scenario.get_terrain(ter_there).ground_type;
 			if(ground_there != main_ground && ground_there != trim_ground) {
 				ter_num_t new_ter = scenario.get_ter_from_ground(trim_ground);
 				if(new_ter > scenario.ter_types.size()) continue;
-				cTerrain& ter_type = scenario.ter_types[new_ter];
+				cTerrain const & ter_type = scenario.get_terrain(new_ter);
 				// We need to be very cautious here.
 				// Only make the change if the terrain already there is the archetype for the ground type
 				// that is the trim terrain of the terrain we're trying to place.
@@ -1978,7 +1979,7 @@ void set_terrain(location l,ter_num_t terrain_type) {
 		adjust_space(l3);
 	}
 	
-	if(scenario.ter_types[terrain_type].special == eTerSpec::IS_A_SIGN) {
+	if(terrain_ground.special == eTerSpec::IS_A_SIGN) {
 		if(!editing_town && (l.x == 0 || l.x == 47 || l.y == 0 || l.y == 47)) {
 			cChoiceDlog("not-at-edge").show();
 			mouse_button_held = false;
@@ -1990,7 +1991,7 @@ void set_terrain(location l,ter_num_t terrain_type) {
 			iter = std::find_if(signs.begin(), signs.end(), [](const sign_loc_t& sign) {
 				if(sign.x == 100) return true;
 				ter_num_t ter = editing_town ? town->terrain(sign.x,sign.y) : current_terrain->terrain[sign.x][sign.y];
-				return scenario.ter_types[ter].special != eTerSpec::IS_A_SIGN;
+				return scenario.get_terrain(ter).special != eTerSpec::IS_A_SIGN;
 			});
 			if(iter == signs.end()) {
 				signs.emplace_back();
@@ -1999,7 +2000,7 @@ void set_terrain(location l,ter_num_t terrain_type) {
 		}
 		static_cast<location&>(*iter) = l;
 		ter_num_t terrain_type = editing_town ? town->terrain(iter->x,iter->y) : current_terrain->terrain[iter->x][iter->y];
-		edit_sign(*iter, iter - signs.begin(), scenario.ter_types[terrain_type].picture);
+		edit_sign(*iter, iter - signs.begin(), scenario.get_terrain(terrain_type).picture);
 		mouse_button_held = false;
 	}
 }
@@ -2030,7 +2031,7 @@ void adjust_space(location l) {
 				continue;
 			}
 			store_ter[dx+1][dy+1] = editing_town ? town->terrain(x,y) : current_terrain->terrain[x][y];
-			cTerrain& ter_type = scenario.ter_types[store_ter[dx+1][dy+1]];
+			cTerrain const &ter_type = scenario.get_terrain(store_ter[dx+1][dy+1]);
 			store_ter2[dx+1][dy+1] = ter_type.trim_ter;
 			store_ground[dx+1][dy+1] = ter_type.ground_type;
 			store_trim[dx+1][dy+1] = ter_type.trim_type;
@@ -2043,7 +2044,7 @@ void adjust_space(location l) {
 	if(store_trim[1][1] >= eTrimType::FRILLS || store_trim[1][1] == eTrimType::WALL)
 		return;
 	
-	bool have_wall = scenario.ter_types[store_ter[1][1]].blockage >= eTerObstruct::BLOCK_MOVE;
+	bool have_wall = scenario.get_terrain(store_ter[1][1]).blockage >= eTerObstruct::BLOCK_MOVE;
 	
 	unsigned int main_ground = store_ground[1][1];
 	long trim_ground = store_ter2[1][1];
@@ -2206,7 +2207,7 @@ void set_special(location spot_hit) {
 
 void town_entry(location spot_hit) {
 	ter_num_t ter = current_terrain->terrain[spot_hit.x][spot_hit.y];
-	if(scenario.ter_types[ter].special != eTerSpec::TOWN_ENTRANCE) {
+	if(scenario.get_terrain(ter).special != eTerSpec::TOWN_ENTRANCE) {
 		showError("This space isn't a town entrance. Town entrances are marked by a small brown castle icon.");
 		return;
 	}
@@ -2214,7 +2215,7 @@ void town_entry(location spot_hit) {
 	for(short x = 0; x < current_terrain->city_locs.size(); x++)
 		if(current_terrain->city_locs[x].spec >= 0) {
 			ter = current_terrain->terrain[current_terrain->city_locs[x].x][current_terrain->city_locs[x].y];
-			if(scenario.ter_types[ter].special != eTerSpec::TOWN_ENTRANCE)
+			if(scenario.get_terrain(ter).special != eTerSpec::TOWN_ENTRANCE)
 				current_terrain->city_locs[x].spec = -1;
 		}
 	auto iter = std::find(current_terrain->city_locs.begin(), current_terrain->city_locs.end(), spot_hit);
@@ -2336,7 +2337,7 @@ void start_town_edit() {
 	shut_down_menus(2);
 	right_sbar->hide();
 	pal_sbar->show();
-	set_string("Drawing mode",scenario.ter_types[current_terrain_type].name);
+	set_string("Drawing mode",scenario.get_terrain(current_terrain_type).name);
 	place_location();
 	copied_spec = -1;
 	for(short i = 0; i < town->max_dim; i++)
@@ -2367,7 +2368,7 @@ void start_out_edit() {
 	pal_sbar->show();
 	shut_down_menus(4);
 	shut_down_menus(1);
-	set_string("Drawing mode",scenario.ter_types[current_terrain_type].name);
+	set_string("Drawing mode",scenario.get_terrain(current_terrain_type).name);
 	place_location();
 	copied_spec = -1;
 	for(short i = 0; i < 48; i++)
diff --git a/src/scenedit/scen.core.cpp b/src/scenedit/scen.core.cpp
index f63a6b18..9fec3636 100644
--- a/src/scenedit/scen.core.cpp
+++ b/src/scenedit/scen.core.cpp
@@ -349,38 +349,34 @@ static bool fill_ter_flag_info(cDialog& me, std::string id, bool losing){
 	return true;
 }
 
+// REMOVEME when setPict will not do fatal error
+bool check_picture_num(cPictNum const &pic, bool noneIsOk)
+try {
+	if (noneIsOk && pic.num==-1)
+		return true;
+	if (pic.num<0)
+		return false;
+	if (pic.type==ePicType::PIC_TER)
+		// REMOVEME when setPict will not do fatal error
+		*ResMgr::textures.get("ter" + std::to_string(1 + pic.num / 50));
+	return true;
+}
+catch(...) {
+	return false;
+}
+
 static void fill_ter_info(cDialog& me, short ter){
-	cTerrain& ter_type = scenario.ter_types[ter];
+	cTerrain const & ter_type = scenario.get_terrain(ter);
 	{
 		cPict& pic_ctrl = dynamic_cast<cPict&>(me["graphic"]);
-		bool bad=false;
-		if (ter_type.get_picture_num().type==ePicType::PIC_TER) {
-			// REMOVEME when setPict will not do fatal error
-			try {
-				*ResMgr::textures.get("ter" + std::to_string(1 + ter_type.get_picture_num().num / 50));
-			}
-			catch(...) {
-				bad=true;
-			}
-		}
-		if (!bad)
+		if (check_picture_num(ter_type.get_picture_num(), false)) // REMOVEME
 			pic_ctrl.setPict(ter_type.get_picture_num());
 		else
 			pic_ctrl.setPict(cPictNum(1999,ePicType::PIC_CUSTOM_TER));
 		me["pict"].setTextToNum(ter_type.picture);
 	}{
 		cPict& pic_ctrl = dynamic_cast<cPict&>(me["seemap"]);
-		bool bad=false;
-		if (ter_type.get_map_picture_num().type==ePicType::PIC_TER) {
-			// REMOVEME when setPict will not do fatal error
-			try {
-				*ResMgr::textures.get("ter" + std::to_string(1 + ter_type.get_map_picture_num().num / 50));
-			}
-			catch(...) {
-				bad=true;
-			}
-		}
-		if (!bad) // FIXME the picture size is bad if we revert to the main picture
+		if (check_picture_num(ter_type.get_map_picture_num(), false)) // REMOVEME
 			pic_ctrl.setPict(ter_type.get_map_picture_num());
 		else
 			pic_ctrl.setPict(cPictNum(1999,ePicType::PIC_CUSTOM_TER));
@@ -453,7 +449,7 @@ static void fill_ter_info(cDialog& me, short ter){
 }
 
 static bool finish_editing_ter(cDialog& me, std::string id, ter_num_t& which) {
-	if(!save_ter_info(me, scenario.ter_types[which])) return true;
+	if(!save_ter_info(me, scenario.get_terrain(which))) return true;
 	
 	if(!me.toast(true)) return true;
 	if(id == "left") {
@@ -473,7 +469,7 @@ static bool finish_editing_ter(cDialog& me, std::string id, ter_num_t& which) {
 }
 
 static bool edit_ter_obj(cDialog& me, ter_num_t which_ter) {
-	cTerrain& ter = scenario.ter_types[which_ter];
+	cTerrain& ter = scenario.get_terrain(which_ter);
 	const pic_num_t pic = ter.picture;
 	cDialog obj_dlg("edit-ter-obj", &me);
 	obj_dlg.attachFocusHandlers([&pic](cDialog& me, std::string fld, bool losing) -> bool {
@@ -507,7 +503,10 @@ static bool edit_ter_obj(cDialog& me, ter_num_t which_ter) {
 		for(int x = 0; x < 4; x++) {
 			for(int y = 0; y < 4; y++) {
 				std::string id = "x" + std::to_string(x) + "y" + std::to_string(y);
-				dynamic_cast<cPict&>(me[id]).setPict(cTerrain::get_picture_num_for_terrain(obj[x][y]));
+				if (check_picture_num(cTerrain::get_picture_num_for_terrain(obj[x][y]), true))
+					dynamic_cast<cPict&>(me[id]).setPict(cTerrain::get_picture_num_for_terrain(obj[x][y]));
+				else
+					dynamic_cast<cPict&>(me[id]).setPict(cPictNum(1999,ePicType::PIC_CUSTOM_TER));
 			}
 		}
 		return true;
diff --git a/src/scenedit/scen.core.hpp b/src/scenedit/scen.core.hpp
index 897e4f3f..9f36e6b5 100644
--- a/src/scenedit/scen.core.hpp
+++ b/src/scenedit/scen.core.hpp
@@ -22,6 +22,7 @@ void edit_scenario_events();
 bool build_scenario();
 bool edit_vehicle(class cVehicle& what, int num, bool is_boat);
 
+bool check_picture_num(cPictNum const &pic, bool noneIsOk);
 bool check_range_msg(cDialog& me,std::string id,bool losing,long min_val,long max_val,std::string fld_name,std::string xtra);
 bool check_range(cDialog& me,std::string id,bool losing,long min_val,long max_val,std::string fld_name);
 bool pick_string(std::string from_file, cDialog& parent, std::string result_fld, std::string str_fld);
diff --git a/src/scenedit/scen.graphics.cpp b/src/scenedit/scen.graphics.cpp
index c82fc2d0..7a015d6a 100644
--- a/src/scenedit/scen.graphics.cpp
+++ b/src/scenedit/scen.graphics.cpp
@@ -88,15 +88,16 @@ extern bool small_any_drawn;
 
 static short get_small_icon(ter_num_t ter){
 	short icon = -1;
-	switch(scenario.ter_types[ter].special){
+	auto const &ter_type=scenario.get_terrain(ter);
+	switch(ter_type.special){
 		case eTerSpec::NONE:
-			icon = scenario.ter_types[ter].flag1;
+			icon = ter_type.flag1;
 			break;
 		case eTerSpec::CHANGE_WHEN_STEP_ON:
 			icon = 87;
 			break;
 		case eTerSpec::DAMAGING:
-			switch(eDamageType(scenario.ter_types[ter].flag3)) {
+			switch(eDamageType(ter_type.flag3)) {
 				case eDamageType::WEAPON:
 					icon = 16;
 					break;
@@ -136,50 +137,50 @@ static short get_small_icon(ter_num_t ter){
 			break;
 		case eTerSpec::DANGEROUS:
 			icon = 12;
-			switch((eStatus)scenario.ter_types[ter].flag3){
+			switch((eStatus)ter_type.flag3){
 				case eStatus::POISONED_WEAPON: // TODO: Do something here
 					break;
 				case eStatus::BLESS_CURSE:
-					icon = scenario.ter_types[ter].flag1 > 0 ? 4 : 5;
+					icon = ter_type.flag1 > 0 ? 4 : 5;
 					break;
 				case eStatus::POISON:
-					if(scenario.ter_types[ter].flag1 > 0)
+					if(ter_type.flag1 > 0)
 						icon = 1;
 					break;
 				case eStatus::HASTE_SLOW:
-					icon = scenario.ter_types[ter].flag1 > 0 ? 6 : 7;
+					icon = ter_type.flag1 > 0 ? 6 : 7;
 					break;
 				case eStatus::INVULNERABLE: // TODO: Do something here
 					break;
 				case eStatus::MAGIC_RESISTANCE: // TODO: Do something here
 					break;
 				case eStatus::WEBS:
-					if(scenario.ter_types[ter].flag1 > 0)
+					if(ter_type.flag1 > 0)
 						icon = 52;
 					break;
 				case eStatus::DISEASE:
-					if(scenario.ter_types[ter].flag1 > 0)
+					if(ter_type.flag1 > 0)
 						icon = 0;
 					break;
 				case eStatus::INVISIBLE: // TODO: Do something here
 					break;
 				case eStatus::DUMB:
-					icon = scenario.ter_types[ter].flag1 > 0 ? 8 : 9;
+					icon = ter_type.flag1 > 0 ? 8 : 9;
 					break;
 				case eStatus::MARTYRS_SHIELD: // TODO: Do something here
 					break;
 				case eStatus::ASLEEP:
-					if(scenario.ter_types[ter].flag1 > 0)
+					if(ter_type.flag1 > 0)
 						icon = 3;
 					break;
 				case eStatus::PARALYZED: // TODO: Do something here
 					break;
 				case eStatus::ACID:
-					if(scenario.ter_types[ter].flag1 > 0)
+					if(ter_type.flag1 > 0)
 						icon = 2;
 					break;
 				case eStatus::FORCECAGE:
-					if(scenario.ter_types[ter].flag1 > 0)
+					if(ter_type.flag1 > 0)
 						icon = 43;
 					break;
 				case eStatus::MAIN: case eStatus::CHARM:
@@ -194,8 +195,8 @@ static short get_small_icon(ter_num_t ter){
 			icon = 94;
 			break;
 		case eTerSpec::UNLOCKABLE:
-			if(scenario.ter_types[ter].flag2 >= 5)
-				icon = (scenario.ter_types[ter].flag2 == 10) ? 96 : 95;
+			if(ter_type.flag2 >= 5)
+				icon = (ter_type.flag2 == 10) ? 96 : 95;
 			else icon = 94;
 			break;
 		case eTerSpec::IS_A_SIGN:
@@ -203,7 +204,7 @@ static short get_small_icon(ter_num_t ter){
 			break;
 		case eTerSpec::CALL_SPECIAL:
 		case eTerSpec::CALL_SPECIAL_WHEN_USED:
-			icon = scenario.ter_types[ter].flag3;
+			icon = ter_type.flag3;
 			break;
 		case eTerSpec::IS_A_CONTAINER:
 			icon = 93;
@@ -213,7 +214,7 @@ static short get_small_icon(ter_num_t ter){
 			icon = 91;
 			break;
 		case eTerSpec::CONVEYOR:
-			switch(scenario.ter_types[ter].flag1){
+			switch(ter_type.flag1){
 				case DIR_N:
 					icon = 78;
 					break;
@@ -292,7 +293,7 @@ static std::vector<short> get_small_icons(location at, ter_num_t t_to_draw) {
 		else icons.push_back(88);
 	}
 	if(editing_town) {
-		if(scenario.ter_types[t_to_draw].light_radius > 0)
+		if(scenario.get_terrain(t_to_draw).light_radius > 0)
 			icons.push_back(83);
 		for(size_t i = 0; i < town->start_locs.size(); i++)
 			if(at == town->start_locs[i]) {
@@ -363,7 +364,7 @@ try {
 catch (...) {
 	if (pict.num==-1) // ok no picture
 		return false;
-	std::cerr << "Error[get_terrain_picture]: can not find picture id=" << pict.num << "type=" << int(pict.type)<< "\n";
+	std::cerr << "Error[get_terrain_picture]: can not find picture id=" << pict.num << ", type=" << int(pict.type)<< "\n";
 	source = *ResMgr::textures.get("errors");
 	from_rect={0,0,40,40};
 	return true;
@@ -584,7 +585,7 @@ void set_up_terrain_buttons(bool reset) {
 					break;
 				}
 				Texture source_gworld;
-				if (get_terrain_picture(scenario.ter_types[i].get_picture_num(), source_gworld, ter_from))
+				if (get_terrain_picture(scenario.get_terrain(i).get_picture_num(), source_gworld, ter_from))
 					rect_draw_some_item(source_gworld,ter_from, mainPtr, draw_rect);
 				small_i = get_small_icon(i);
 				tiny_from = base_small_button_from;
@@ -927,7 +928,7 @@ void draw_terrain(){
 							}
 						}
 					} else if(overall_mode == MODE_DRAWING) {
-						cTerrain& ter = scenario.ter_types[current_terrain_type];
+						cTerrain& ter = scenario.get_terrain(current_terrain_type);
 						if(ter.obj_num > 0) {
 							// TODO: Don't do this if auto-completion of large terrain objects is disabled
 							for(int x = 0; x < ter.obj_size.x; x++) {
@@ -1146,7 +1147,7 @@ void draw_one_terrain_spot (short i,short j,ter_num_t terrain_to_draw) {
 	
 	rectangle source_rect;
 	Texture source_gworld;
-	if (!get_terrain_picture(scenario.ter_types[terrain_to_draw].get_picture_num(), source_gworld, source_rect))
+	if (!get_terrain_picture(scenario.get_terrain(terrain_to_draw).get_picture_num(), source_gworld, source_rect))
 		return;
 
 	location where_draw;
@@ -1167,7 +1168,7 @@ void draw_one_tiny_terrain_spot (short i,short j,ter_num_t terrain_to_draw,short
 	Texture source_gworld;
 	rectangle dest_rect = {0,0,size,size};
 	dest_rect.offset(8 + TER_RECT_UL_X + size * i, 8 + TER_RECT_UL_Y + size * j);
-	if (get_terrain_picture(scenario.ter_types[terrain_to_draw].get_map_picture_num(), source_gworld, from_rect))
+	if (get_terrain_picture(scenario.get_terrain(terrain_to_draw).get_map_picture_num(), source_gworld, from_rect))
 		rect_draw_some_item(source_gworld, from_rect, mainPtr, dest_rect);
 	if(road) {
 		rectangle road_rect = dest_rect;
@@ -1206,7 +1207,7 @@ rectangle get_template_rect (unsigned short type_wanted) {
 	rectangle store_rect;
 	short picture_wanted;
 	
-	picture_wanted = scenario.ter_types[type_wanted].picture;
+	picture_wanted = scenario.get_terrain(type_wanted).picture;
 	if(picture_wanted >= 1000)
 		picture_wanted = 0;
 	picture_wanted = picture_wanted % 50;
@@ -1252,7 +1253,7 @@ void draw_frames() {
 static void place_selected_terrain(ter_num_t ter, rectangle draw_rect) {
 	rectangle source_rect;
 	Texture source_gworld;
-	if (get_terrain_picture(scenario.ter_types[ter].get_picture_num(), source_gworld, source_rect))
+	if (get_terrain_picture(scenario.get_terrain(ter).get_picture_num(), source_gworld, source_rect))
 		rect_draw_some_item(source_gworld,source_rect, mainPtr,draw_rect);
 
 	short small_i = get_small_icon(ter);
@@ -1289,7 +1290,7 @@ void place_location() {
 					int first = pal_sbar->getPosition() * 16;
 					switch(draw_mode) {
 						case DRAW_TERRAIN:
-							if(first + i < scenario.ter_types.size())
+							if(first+i >= 0 && first + i < scenario.ter_types.size())
 								sout << "Terrain: " << scenario.ter_types[first + i].name;
 							break;
 						case DRAW_ITEM:
@@ -1578,7 +1579,7 @@ void take_field_type(short i,short j,eFieldType field_type) {
 bool container_there(location l) {
 	if(!editing_town)
 		return false;
-	if(scenario.ter_types[town->terrain(l.x,l.y)].special == eTerSpec::IS_A_CONTAINER)
+	if(scenario.get_terrain(town->terrain(l.x,l.y)).special == eTerSpec::IS_A_CONTAINER)
 		return true;
 	if(is_field_type(l.x,l.y, OBJECT_BARREL))
 		return true;
diff --git a/src/scenedit/scen.townout.cpp b/src/scenedit/scen.townout.cpp
index 5773195c..98ecc86c 100644
--- a/src/scenedit/scen.townout.cpp
+++ b/src/scenedit/scen.townout.cpp
@@ -368,7 +368,11 @@ void edit_sign(sign_loc_t& which_sign,short num,short picture) {
 	cDialog sign_dlg("edit-sign");
 	sign_dlg["cancel"].attachClickHandler(std::bind(&cDialog::toast, &sign_dlg, false));
 	sign_dlg["okay"].attachClickHandler(std::bind(edit_sign_event_filter, _1, std::ref(which_sign)));
-	dynamic_cast<cPict&>(sign_dlg["pic"]).setPict(cTerrain::get_picture_num_for_terrain(picture)); // checkme: does this really need to be some terrain?
+	if (check_picture_num(cTerrain::get_picture_num_for_terrain(picture), false)) // REMOVEME
+		dynamic_cast<cPict&>(sign_dlg["pic"]).setPict(cTerrain::get_picture_num_for_terrain(picture)); // checkme: does this really need to be some terrain?
+	else
+		dynamic_cast<cPict&>(sign_dlg["pic"]).setPict(cPictNum(1999,ePicType::PIC_CUSTOM_TER));
+
 	
 	sign_dlg["num"].setTextToNum(num);
 	sign_dlg["text"].setText(which_sign.text);