diff --git a/graphics/battle_transitions/rayquaza.png b/graphics/battle_transitions/rayquaza.png
index 5c3a91474..00df7d741 100644
Binary files a/graphics/battle_transitions/rayquaza.png and b/graphics/battle_transitions/rayquaza.png differ
diff --git a/graphics/battle_transitions/regis.png b/graphics/battle_transitions/regis.png
index a08310737..4926b165b 100644
Binary files a/graphics/battle_transitions/regis.png and b/graphics/battle_transitions/regis.png differ
diff --git a/graphics/picture_frame/lobby.png b/graphics/picture_frame/lobby.png
index 1b7da4a1a..2f04105ff 100644
Binary files a/graphics/picture_frame/lobby.png and b/graphics/picture_frame/lobby.png differ
diff --git a/graphics_file_rules.mk b/graphics_file_rules.mk
index 42b1e6d74..3335179d1 100644
--- a/graphics_file_rules.mk
+++ b/graphics_file_rules.mk
@@ -64,31 +64,31 @@ $(CASTFORMGFXDIR)/shiny.gbapal: $(CASTFORMGFXDIR)/shiny_normal_form.gbapal \
 ### Tilesets ###
 
 $(TILESETGFXDIR)/secondary/petalburg/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 159
+	$(GFX) $< $@ -num_tiles 159 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/rustboro/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 498
+	$(GFX) $< $@ -num_tiles 498 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/dewford/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 503
+	$(GFX) $< $@ -num_tiles 503 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/slateport/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 504
+	$(GFX) $< $@ -num_tiles 504 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/mauville/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 503
+	$(GFX) $< $@ -num_tiles 503 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/lavaridge/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 450
+	$(GFX) $< $@ -num_tiles 450 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/fortree/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 493
+	$(GFX) $< $@ -num_tiles 493 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/pacifidlog/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 504
+	$(GFX) $< $@ -num_tiles 504 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/sootopolis/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 328
+	$(GFX) $< $@ -num_tiles 328 -Wnum_tiles
 
 SOOTOPOLISANIMDIR := $(TILESETGFXDIR)/secondary/sootopolis/anim
 
@@ -125,169 +125,169 @@ $(SOOTOPOLISANIMDIR)/stormy_water/7.4bpp: $(SOOTOPOLISANIMDIR)/stormy_water/7_ky
 	@cat $^ >$@
 
 $(TILESETGFXDIR)/secondary/battle_frontier_outside_west/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 508
+	$(GFX) $< $@ -num_tiles 508 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/battle_frontier_outside_east/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 508
+	$(GFX) $< $@ -num_tiles 508 -Wnum_tiles
 
 $(TILESETGFXDIR)/primary/building/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 502
+	$(GFX) $< $@ -num_tiles 502 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/shop/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 502
+	$(GFX) $< $@ -num_tiles 502 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/pokemon_center/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 478
+	$(GFX) $< $@ -num_tiles 478 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/cave/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 425
+	$(GFX) $< $@ -num_tiles 425 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/pokemon_school/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 278
+	$(GFX) $< $@ -num_tiles 278 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/pokemon_fan_club/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 319
+	$(GFX) $< $@ -num_tiles 319 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/unused_1/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 17
+	$(GFX) $< $@ -num_tiles 17 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/meteor_falls/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 460
+	$(GFX) $< $@ -num_tiles 460 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/oceanic_museum/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 319
+	$(GFX) $< $@ -num_tiles 319 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/cable_club/unknown_tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 120
+	$(GFX) $< $@ -num_tiles 120 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/seashore_house/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 312
+	$(GFX) $< $@ -num_tiles 312 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/pretty_petal_flower_shop/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 345
+	$(GFX) $< $@ -num_tiles 345 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/pokemon_day_care/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 355
+	$(GFX) $< $@ -num_tiles 355 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/secret_base/brown_cave/unused_tiles.4bpp: $(TILESETGFXDIR)/secondary/secret_base/brown_cave/tiles.png
-	$(GFX) $< $@ -num_tiles 82
+	$(GFX) $< $@ -num_tiles 82 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/secret_base/tree/unused_tiles.4bpp: $(TILESETGFXDIR)/secondary/secret_base/tree/tiles.png
-	$(GFX) $< $@ -num_tiles 82
+	$(GFX) $< $@ -num_tiles 82 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/secret_base/shrub/unused_tiles.4bpp: $(TILESETGFXDIR)/secondary/secret_base/shrub/tiles.png
-	$(GFX) $< $@ -num_tiles 82
+	$(GFX) $< $@ -num_tiles 82 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/secret_base/blue_cave/unused_tiles.4bpp: $(TILESETGFXDIR)/secondary/secret_base/blue_cave/tiles.png
-	$(GFX) $< $@ -num_tiles 82
+	$(GFX) $< $@ -num_tiles 82 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/secret_base/yellow_cave/unused_tiles.4bpp: $(TILESETGFXDIR)/secondary/secret_base/yellow_cave/tiles.png
-	$(GFX) $< $@ -num_tiles 82
+	$(GFX) $< $@ -num_tiles 82 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/secret_base/red_cave/unused_tiles.4bpp: $(TILESETGFXDIR)/secondary/secret_base/red_cave/tiles.png
-	$(GFX) $< $@ -num_tiles 82
+	$(GFX) $< $@ -num_tiles 82 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/secret_base/brown_cave/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 83
+	$(GFX) $< $@ -num_tiles 83 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/secret_base/tree/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 83
+	$(GFX) $< $@ -num_tiles 83 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/secret_base/shrub/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 83
+	$(GFX) $< $@ -num_tiles 83 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/secret_base/blue_cave/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 83
+	$(GFX) $< $@ -num_tiles 83 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/secret_base/yellow_cave/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 83
+	$(GFX) $< $@ -num_tiles 83 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/secret_base/red_cave/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 83
+	$(GFX) $< $@ -num_tiles 83 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/inside_of_truck/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 62
+	$(GFX) $< $@ -num_tiles 62 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/contest/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 430
+	$(GFX) $< $@ -num_tiles 430 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/lilycove_museum/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 431
+	$(GFX) $< $@ -num_tiles 431 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/lab/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 500
+	$(GFX) $< $@ -num_tiles 500 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/underwater/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 500
+	$(GFX) $< $@ -num_tiles 500 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/generic_building/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 509
+	$(GFX) $< $@ -num_tiles 509 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/mauville_game_corner/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 469
+	$(GFX) $< $@ -num_tiles 469 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/unused_2/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 150
+	$(GFX) $< $@ -num_tiles 150 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/rustboro_gym/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 60
+	$(GFX) $< $@ -num_tiles 60 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/dewford_gym/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 61
+	$(GFX) $< $@ -num_tiles 61 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/lavaridge_gym/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 54
+	$(GFX) $< $@ -num_tiles 54 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/petalburg_gym/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 148
+	$(GFX) $< $@ -num_tiles 148 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/fortree_gym/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 61
+	$(GFX) $< $@ -num_tiles 61 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/mossdeep_gym/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 82
+	$(GFX) $< $@ -num_tiles 82 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/sootopolis_gym/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 484
+	$(GFX) $< $@ -num_tiles 484 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/trick_house_puzzle/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 294
+	$(GFX) $< $@ -num_tiles 294 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/inside_ship/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 342
+	$(GFX) $< $@ -num_tiles 342 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/elite_four/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 505
+	$(GFX) $< $@ -num_tiles 505 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/battle_frontier/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 310
+	$(GFX) $< $@ -num_tiles 310 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/battle_factory/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 424
+	$(GFX) $< $@ -num_tiles 424 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/battle_pike/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 382
+	$(GFX) $< $@ -num_tiles 382 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/mirage_tower/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 420
+	$(GFX) $< $@ -num_tiles 420 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/mossdeep_game_corner/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 95
+	$(GFX) $< $@ -num_tiles 95 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/island_harbor/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 503
+	$(GFX) $< $@ -num_tiles 503 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/trainer_hill/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 374
+	$(GFX) $< $@ -num_tiles 374 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/navel_rock/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 420
+	$(GFX) $< $@ -num_tiles 420 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/battle_frontier_ranking_hall/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 136
+	$(GFX) $< $@ -num_tiles 136 -Wnum_tiles
 
 $(TILESETGFXDIR)/secondary/mystery_events_house/tiles.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 509
+	$(GFX) $< $@ -num_tiles 509 -Wnum_tiles
 
 
 
@@ -335,13 +335,13 @@ graphics/title_screen/pokemon_logo.gbapal: %.gbapal: %.pal
 	$(GFX) $< $@ -num_colors 224
 
 graphics/pokemon_jump/bg.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 63
+	$(GFX) $< $@ -num_tiles 63 -Wnum_tiles
 
 graphics/pokenav/region_map.8bpp: %.8bpp: %.png
-	$(GFX) $< $@ -num_tiles 233
+	$(GFX) $< $@ -num_tiles 233 -Wnum_tiles
 
 $(MISCGFXDIR)/japanese_hof.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 29
+	$(GFX) $< $@ -num_tiles 29 -Wnum_tiles
 
 $(BATINTGFXDIR)/textbox.gbapal: $(BATINTGFXDIR)/textbox_0.gbapal \
                                 $(BATINTGFXDIR)/textbox_1.gbapal
@@ -385,10 +385,10 @@ $(UNUSEDGFXDIR)/redyellowgreen_frame.bin: $(UNUSEDGFXDIR)/red_frame.bin \
 	@cat $^ >$@
 
 $(UNUSEDGFXDIR)/color_frames.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 353
+	$(GFX) $< $@ -num_tiles 353 -Wnum_tiles
 
 $(BATINTGFXDIR)/unused_window2bar.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 5
+	$(GFX) $< $@ -num_tiles 5 -Wnum_tiles
 
 $(JPCONTESTGFXDIR)/composite_1.4bpp: $(JPCONTESTGFXDIR)/frame_1.4bpp \
                                      $(JPCONTESTGFXDIR)/floor.4bpp \
@@ -404,7 +404,7 @@ $(JPCONTESTGFXDIR)/composite_2.4bpp: $(JPCONTESTGFXDIR)/interface.4bpp \
 	@cat $^ >$@
 
 $(JPCONTESTGFXDIR)/voltage.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 36
+	$(GFX) $< $@ -num_tiles 36 -Wnum_tiles
 
 $(BTLANMSPRGFXDIR)/ice_crystals.4bpp: $(BTLANMSPRGFXDIR)/ice_crystals_0.4bpp \
                                       $(BTLANMSPRGFXDIR)/ice_crystals_1.4bpp \
@@ -426,13 +426,13 @@ $(BTLANMSPRGFXDIR)/spark.4bpp: $(BTLANMSPRGFXDIR)/spark_0.4bpp \
 	@cat $^ >$@
 
 $(MASKSGFXDIR)/unused_level_up.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 14
+	$(GFX) $< $@ -num_tiles 14 -Wnum_tiles
 
 $(BATTRANSGFXDIR)/vs_frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 16
+	$(GFX) $< $@ -num_tiles 16 -Wnum_tiles
 
 graphics/party_menu/bg.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 62
+	$(GFX) $< $@ -num_tiles 62 -Wnum_tiles
 
 $(TYPESGFXDIR)/move_types.4bpp: $(types:%=$(TYPESGFXDIR)/%.4bpp) $(contest_types:%=$(TYPESGFXDIR)/contest_%.4bpp)
 	@cat $^ >$@
@@ -443,29 +443,29 @@ $(TYPESGFXDIR)/move_types.gbapal: $(TYPESGFXDIR)/move_types_1.gbapal \
 	@cat $^ >$@
 
 graphics/bag/menu.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 53
+	$(GFX) $< $@ -num_tiles 53 -Wnum_tiles
 
 $(RAYQUAZAGFXDIR)/scene_2/rayquaza.8bpp: %.8bpp: %.png
-	$(GFX) $< $@ -num_tiles 227
+	$(GFX) $< $@ -num_tiles 227 -Wnum_tiles
 
 $(RAYQUAZAGFXDIR)/scene_2/bg.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 313
+	$(GFX) $< $@ -num_tiles 313 -Wnum_tiles
 
 $(RAYQUAZAGFXDIR)/scene_3/rayquaza.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 124
+	$(GFX) $< $@ -num_tiles 124 -Wnum_tiles
 
 $(RAYQUAZAGFXDIR)/scene_3/rayquaza_tail_fix.4bpp: $(RAYQUAZAGFXDIR)/scene_3/rayquaza_tail.4bpp
 	cp $< $@
 	head -c 12 /dev/zero >> $@
 
 $(RAYQUAZAGFXDIR)/scene_4/streaks.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 19
+	$(GFX) $< $@ -num_tiles 19 -Wnum_tiles
 
 $(RAYQUAZAGFXDIR)/scene_4/rayquaza.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 155
+	$(GFX) $< $@ -num_tiles 155 -Wnum_tiles
 
 graphics/picture_frame/lobby.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 86
+	$(GFX) $< $@ -num_tiles 86 -Wnum_tiles
 
 $(ROULETTEGFXDIR)/roulette_tilt.4bpp: $(ROULETTEGFXDIR)/shroomish.4bpp \
                                       $(ROULETTEGFXDIR)/tailow.4bpp
@@ -478,10 +478,10 @@ $(ROULETTEGFXDIR)/wheel_icons.4bpp: $(ROULETTEGFXDIR)/wynaut.4bpp \
 	@cat $^ >$@
 
 $(BATTRANSGFXDIR)/regis.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 53
+	$(GFX) $< $@ -num_tiles 53 -Wnum_tiles
 
 $(BATTRANSGFXDIR)/rayquaza.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 938
+	$(GFX) $< $@ -num_tiles 938 -Wnum_tiles
 
 $(BATTRANSGFXDIR)/frontier_square_1.4bpp: $(BATTRANSGFXDIR)/frontier_squares_blanktiles.4bpp \
                                           $(BATTRANSGFXDIR)/frontier_squares_1.4bpp
@@ -504,20 +504,20 @@ $(SLOTMACHINEGFXDIR)/reel_time_gfx.4bpp: $(SLOTMACHINEGFXDIR)/reel_time_pikachu.
 	@cat $^ >$@
 
 graphics/birch_speech/unused_beauty.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 822
+	$(GFX) $< $@ -num_tiles 822 -Wnum_tiles
 
 
 
 ### Pokémon Storage System ###
 
 $(WALLPAPERGFXDIR)/forest/frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 55
+	$(GFX) $< $@ -num_tiles 55 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/forest/tiles.4bpp: $(WALLPAPERGFXDIR)/forest/frame.4bpp $(WALLPAPERGFXDIR)/forest/bg.4bpp
 	@cat $^ >$@
 
 $(WALLPAPERGFXDIR)/city/frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 52
+	$(GFX) $< $@ -num_tiles 52 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/city/tiles.4bpp: $(WALLPAPERGFXDIR)/city/frame.4bpp $(WALLPAPERGFXDIR)/city/bg.4bpp
 	@cat $^ >$@
@@ -526,97 +526,97 @@ $(WALLPAPERGFXDIR)/desert/tiles.4bpp: $(WALLPAPERGFXDIR)/desert/frame.4bpp $(WAL
 	@cat $^ >$@
 
 $(WALLPAPERGFXDIR)/savanna/frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 45
+	$(GFX) $< $@ -num_tiles 45 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/savanna/bg.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 23
+	$(GFX) $< $@ -num_tiles 23 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/savanna/tiles.4bpp: $(WALLPAPERGFXDIR)/savanna/frame.4bpp $(WALLPAPERGFXDIR)/savanna/bg.4bpp
 	@cat $^ >$@
 
 $(WALLPAPERGFXDIR)/crag/frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 49
+	$(GFX) $< $@ -num_tiles 49 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/crag/tiles.4bpp: $(WALLPAPERGFXDIR)/crag/frame.4bpp $(WALLPAPERGFXDIR)/crag/bg.4bpp
 	@cat $^ >$@
 
 $(WALLPAPERGFXDIR)/volcano/frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 56
+	$(GFX) $< $@ -num_tiles 56 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/volcano/tiles.4bpp: $(WALLPAPERGFXDIR)/volcano/frame.4bpp $(WALLPAPERGFXDIR)/volcano/bg.4bpp
 	@cat $^ >$@
 
 $(WALLPAPERGFXDIR)/snow/frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 57
+	$(GFX) $< $@ -num_tiles 57 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/snow/tiles.4bpp: $(WALLPAPERGFXDIR)/snow/frame.4bpp $(WALLPAPERGFXDIR)/snow/bg.4bpp
 	@cat $^ >$@
 
 $(WALLPAPERGFXDIR)/cave/frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 55
+	$(GFX) $< $@ -num_tiles 55 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/cave/tiles.4bpp: $(WALLPAPERGFXDIR)/cave/frame.4bpp $(WALLPAPERGFXDIR)/cave/bg.4bpp
 	@cat $^ >$@
 
 $(WALLPAPERGFXDIR)/beach/frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 46
+	$(GFX) $< $@ -num_tiles 46 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/beach/bg.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 23
+	$(GFX) $< $@ -num_tiles 23 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/beach/tiles.4bpp: $(WALLPAPERGFXDIR)/beach/frame.4bpp $(WALLPAPERGFXDIR)/beach/bg.4bpp
 	@cat $^ >$@
 
 $(WALLPAPERGFXDIR)/seafloor/frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 54
+	$(GFX) $< $@ -num_tiles 54 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/seafloor/tiles.4bpp: $(WALLPAPERGFXDIR)/seafloor/frame.4bpp $(WALLPAPERGFXDIR)/seafloor/bg.4bpp
 	@cat $^ >$@
 
 $(WALLPAPERGFXDIR)/river/frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 51
+	$(GFX) $< $@ -num_tiles 51 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/river/bg.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 11
+	$(GFX) $< $@ -num_tiles 11 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/river/tiles.4bpp: $(WALLPAPERGFXDIR)/river/frame.4bpp $(WALLPAPERGFXDIR)/river/bg.4bpp
 	@cat $^ >$@
 
 $(WALLPAPERGFXDIR)/sky/frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 45
+	$(GFX) $< $@ -num_tiles 45 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/sky/tiles.4bpp: $(WALLPAPERGFXDIR)/sky/frame.4bpp $(WALLPAPERGFXDIR)/sky/bg.4bpp
 	@cat $^ >$@
 
 $(WALLPAPERGFXDIR)/polkadot/frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 54
+	$(GFX) $< $@ -num_tiles 54 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/polkadot/tiles.4bpp: $(WALLPAPERGFXDIR)/polkadot/frame.4bpp $(WALLPAPERGFXDIR)/polkadot/bg.4bpp
 	@cat $^ >$@
 
 $(WALLPAPERGFXDIR)/pokecenter/frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 35
+	$(GFX) $< $@ -num_tiles 35 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/pokecenter/tiles.4bpp: $(WALLPAPERGFXDIR)/pokecenter/frame.4bpp $(WALLPAPERGFXDIR)/pokecenter/bg.4bpp
 	@cat $^ >$@
 
 $(WALLPAPERGFXDIR)/machine/frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 33
+	$(GFX) $< $@ -num_tiles 33 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/machine/tiles.4bpp: $(WALLPAPERGFXDIR)/machine/frame.4bpp $(WALLPAPERGFXDIR)/machine/bg.4bpp
 	@cat $^ >$@
 
 $(WALLPAPERGFXDIR)/plain/frame.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 18
+	$(GFX) $< $@ -num_tiles 18 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/plain/tiles.4bpp: $(WALLPAPERGFXDIR)/plain/frame.4bpp $(WALLPAPERGFXDIR)/plain/bg.4bpp
 	@cat $^ >$@
 
 $(WALLPAPERGFXDIR)/friends_frame1.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 57
+	$(GFX) $< $@ -num_tiles 57 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/friends_frame2.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 57
+	$(GFX) $< $@ -num_tiles 57 -Wnum_tiles
 
 $(WALLPAPERGFXDIR)/zigzagoon/tiles.4bpp: $(WALLPAPERGFXDIR)/friends_frame1.4bpp $(WALLPAPERGFXDIR)/zigzagoon/bg.4bpp
 	@cat $^ >$@
@@ -667,13 +667,13 @@ $(WALLPAPERGFXDIR)/whiscash/tiles.4bpp: $(WALLPAPERGFXDIR)/friends_frame2.4bpp $
 	@cat $^ >$@
 
 $(OBJEVENTGFXDIR)/pics/effects/unknown_4F6D38/0.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 11
+	$(GFX) $< $@ -num_tiles 11 -Wnum_tiles
 
 $(INTERFACEGFXDIR)/selector_outline.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 8
+	$(GFX) $< $@ -num_tiles 8 -Wnum_tiles
 	
 $(BATTRANSGFXDIR)/frontier_logo_center.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 43
+	$(GFX) $< $@ -num_tiles 43 -Wnum_tiles
 
 
 
@@ -695,19 +695,19 @@ $(PKNAVOPTIONSGFXDIR)/options.4bpp: $(PKNAVOPTIONSGFXDIR)/hoenn_map.4bpp \
 	@cat $^ >$@
 
 $(PKNAVGFXDIR)/header.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 53
+	$(GFX) $< $@ -num_tiles 53 -Wnum_tiles
 
 $(PKNAVGFXDIR)/device_outline.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 53
+	$(GFX) $< $@ -num_tiles 53 -Wnum_tiles
 	
 $(PKNAVGFXDIR)/match_call/ui.4bpp: %.4bpp: %.png
-	$(GFX) $< $@ -num_tiles 13
+	$(GFX) $< $@ -num_tiles 13 -Wnum_tiles
 
 $(POKEDEXGFXDIR)/region_map.8bpp: %.8bpp: %.png
-	$(GFX) $< $@ -num_tiles 232
+	$(GFX) $< $@ -num_tiles 232 -Wnum_tiles
 
 $(POKEDEXGFXDIR)/region_map_affine.8bpp: %.8bpp: %.png
-	$(GFX) $< $@ -num_tiles 233
+	$(GFX) $< $@ -num_tiles 233 -Wnum_tiles
 
 $(STARTERGFXDIR)/birch_help.4bpp: $(STARTERGFXDIR)/birch_bag.4bpp $(STARTERGFXDIR)/birch_grass.4bpp
 	@cat $^ >$@
diff --git a/tools/gbagfx/gfx.c b/tools/gbagfx/gfx.c
index 4e85953fd..832e9bb39 100644
--- a/tools/gbagfx/gfx.c
+++ b/tools/gbagfx/gfx.c
@@ -397,7 +397,7 @@ void ReadImage(char *path, int tilesWidth, int bitDepth, int metatileWidth, int
 	free(buffer);
 }
 
-void WriteImage(char *path, int numTiles, int bitDepth, int metatileWidth, int metatileHeight, struct Image *image, bool invertColors)
+void WriteImage(char *path, enum NumTilesMode numTilesMode, int numTiles, int bitDepth, int metatileWidth, int metatileHeight, struct Image *image, bool invertColors)
 {
 	int tileSize = bitDepth * 8;
 
@@ -424,7 +424,8 @@ void WriteImage(char *path, int numTiles, int bitDepth, int metatileWidth, int m
 		FATAL_ERROR("The specified number of tiles (%d) is greater than the maximum possible value (%d).\n", numTiles, maxNumTiles);
 
 	int bufferSize = numTiles * tileSize;
-	unsigned char *buffer = malloc(bufferSize);
+	int maxBufferSize = maxNumTiles * tileSize;
+	unsigned char *buffer = malloc(maxBufferSize);
 
 	if (buffer == NULL)
 		FATAL_ERROR("Failed to allocate memory for pixels.\n");
@@ -433,17 +434,36 @@ void WriteImage(char *path, int numTiles, int bitDepth, int metatileWidth, int m
 
 	switch (bitDepth) {
 	case 1:
-		ConvertToTiles1Bpp(image->pixels, buffer, numTiles, metatilesWide, metatileWidth, metatileHeight, invertColors);
+		ConvertToTiles1Bpp(image->pixels, buffer, maxNumTiles, metatilesWide, metatileWidth, metatileHeight, invertColors);
 		break;
 	case 4:
-		ConvertToTiles4Bpp(image->pixels, buffer, numTiles, metatilesWide, metatileWidth, metatileHeight, invertColors);
+		ConvertToTiles4Bpp(image->pixels, buffer, maxNumTiles, metatilesWide, metatileWidth, metatileHeight, invertColors);
 		break;
 	case 8:
-		ConvertToTiles8Bpp(image->pixels, buffer, numTiles, metatilesWide, metatileWidth, metatileHeight, invertColors);
+		ConvertToTiles8Bpp(image->pixels, buffer, maxNumTiles, metatilesWide, metatileWidth, metatileHeight, invertColors);
 		break;
 	}
 
-	WriteWholeFile(path, buffer, bufferSize);
+	bool zeroPadded = true;
+	for (int i = bufferSize; i < maxBufferSize && zeroPadded; i++) {
+		if (buffer[i] != 0)
+		{
+			switch (numTilesMode)
+			{
+			case NUM_TILES_IGNORE:
+				break;
+			case NUM_TILES_WARN:
+				fprintf(stderr, "Ignoring -num_tiles %d because tile %d contains non-transparent pixels.\n", numTiles, 1 + i / tileSize);
+				zeroPadded = false;
+				break;
+			case NUM_TILES_ERROR:
+				FATAL_ERROR("Tile %d contains non-transparent pixels.\n", 1 + i / tileSize);
+				break;
+			}
+		}
+	}
+
+	WriteWholeFile(path, buffer, zeroPadded ? bufferSize : maxBufferSize);
 
 	free(buffer);
 }
diff --git a/tools/gbagfx/gfx.h b/tools/gbagfx/gfx.h
index edb9e62c4..f1dbfcf4f 100644
--- a/tools/gbagfx/gfx.h
+++ b/tools/gbagfx/gfx.h
@@ -44,8 +44,14 @@ struct Image {
 	bool isAffine;
 };
 
+enum NumTilesMode {
+    NUM_TILES_IGNORE,
+    NUM_TILES_WARN,
+    NUM_TILES_ERROR,
+};
+
 void ReadImage(char *path, int tilesWidth, int bitDepth, int metatileWidth, int metatileHeight, struct Image *image, bool invertColors);
-void WriteImage(char *path, int numTiles, int bitDepth, int metatileWidth, int metatileHeight, struct Image *image, bool invertColors);
+void WriteImage(char *path, enum NumTilesMode numTilesMode, int numTiles, int bitDepth, int metatileWidth, int metatileHeight, struct Image *image, bool invertColors);
 void FreeImage(struct Image *image);
 void ReadGbaPalette(char *path, struct Palette *palette);
 void WriteGbaPalette(char *path, struct Palette *palette);
diff --git a/tools/gbagfx/main.c b/tools/gbagfx/main.c
index cf3031696..5d4faacab 100644
--- a/tools/gbagfx/main.c
+++ b/tools/gbagfx/main.c
@@ -77,7 +77,7 @@ void ConvertPngToGba(char *inputPath, char *outputPath, struct PngToGbaOptions *
 
     ReadPng(inputPath, &image);
 
-    WriteImage(outputPath, options->numTiles, options->bitDepth, options->metatileWidth, options->metatileHeight, &image, !image.hasPalette);
+    WriteImage(outputPath, options->numTilesMode, options->numTiles, options->bitDepth, options->metatileWidth, options->metatileHeight, &image, !image.hasPalette);
 
     FreeImage(&image);
 }
@@ -179,6 +179,7 @@ void HandlePngToGbaCommand(char *inputPath, char *outputPath, int argc, char **a
     char *outputFileExtension = GetFileExtensionAfterDot(outputPath);
     int bitDepth = outputFileExtension[0] - '0';
     struct PngToGbaOptions options;
+    options.numTilesMode = NUM_TILES_IGNORE;
     options.numTiles = 0;
     options.bitDepth = bitDepth;
     options.metatileWidth = 1;
@@ -203,6 +204,12 @@ void HandlePngToGbaCommand(char *inputPath, char *outputPath, int argc, char **a
             if (options.numTiles < 1)
                 FATAL_ERROR("Number of tiles must be positive.\n");
         }
+        else if (strcmp(option, "-Wnum_tiles") == 0) {
+            options.numTilesMode = NUM_TILES_WARN;
+        }
+        else if (strcmp(option, "-Werror=num_tiles") == 0) {
+            options.numTilesMode = NUM_TILES_ERROR;
+        }
         else if (strcmp(option, "-mwidth") == 0)
         {
             if (i + 1 >= argc)
diff --git a/tools/gbagfx/options.h b/tools/gbagfx/options.h
index 3b038f572..250b72345 100644
--- a/tools/gbagfx/options.h
+++ b/tools/gbagfx/options.h
@@ -4,6 +4,7 @@
 #define OPTIONS_H
 
 #include <stdbool.h>
+#include "gfx.h"
 
 struct GbaToPngOptions {
     char *paletteFilePath;
@@ -18,6 +19,7 @@ struct GbaToPngOptions {
 
 struct PngToGbaOptions {
     int numTiles;
+    enum NumTilesMode numTilesMode;
     int bitDepth;
     int metatileWidth;
     int metatileHeight;