diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..ac7cff2
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1 @@
+src/img/*.png
diff --git a/Tupfile.ini b/Tupfile.ini
new file mode 100644
index 0000000..e69de29
diff --git a/justfile b/justfile
index 5ca317c..f71d7ed 100644
--- a/justfile
+++ b/justfile
@@ -1,7 +1,7 @@
 bin := "Rush.pdx"
 
 alias b := build
-build:
+build: cook-assets
     pdc --quiet --skip-unknown src {{ bin }}
 
 alias s := simu
@@ -10,3 +10,4 @@ simu: build
 
 cook-assets:
     @(which aseprite > /dev/null) || (echo "Missing aseprite program"; exit 1)
+    tup
diff --git a/src/img/Tupfile b/src/img/Tupfile
new file mode 100644
index 0000000..04c14dc
--- /dev/null
+++ b/src/img/Tupfile
@@ -0,0 +1,2 @@
+: level_01.ase |> aseprite --batch --export-tileset %f --sheet %o |> %B-table-32-32.png
+: player.ase |> aseprite --batch %f --save-as %o |> %B.png
diff --git a/src/img/bg_atlas-table-32-32.png b/src/img/bg_atlas-table-32-32.png
deleted file mode 100644
index 8a58543..0000000
Binary files a/src/img/bg_atlas-table-32-32.png and /dev/null differ
diff --git a/src/img/bg_atlas.pxo b/src/img/bg_atlas.pxo
deleted file mode 100644
index 351d70b..0000000
Binary files a/src/img/bg_atlas.pxo and /dev/null differ
diff --git a/src/img/level_01.aseprite b/src/img/level_01.ase
similarity index 74%
rename from src/img/level_01.aseprite
rename to src/img/level_01.ase
index 0e0c3dc..ca8a6dd 100644
Binary files a/src/img/level_01.aseprite and b/src/img/level_01.ase differ
diff --git a/src/img/player.ase b/src/img/player.ase
new file mode 100644
index 0000000..6454979
Binary files /dev/null and b/src/img/player.ase differ
diff --git a/src/img/player.pxo b/src/img/player.pxo
deleted file mode 100644
index 77d9161..0000000
Binary files a/src/img/player.pxo and /dev/null differ
diff --git a/src/main.lua b/src/main.lua
index 98db2ae..fa5c03e 100644
--- a/src/main.lua
+++ b/src/main.lua
@@ -16,7 +16,7 @@ function gameInit()
   playerSprite:moveTo(200, 120) -- (200,120) is the center of the Playdate screen
   playerSprite:add()
 
-  atlas = gfx.imagetable.new("img/bg_atlas")
+  atlas = gfx.imagetable.new("img/level_01")
 end
 
 gameInit()
@@ -47,5 +47,5 @@ function playdate.update()
 
   gfx.sprite.update()
   playdate.timer.updateTimers()
-  atlas:drawImage(1, 32, 32)
+  atlas:drawImage(2, 32, 32)
 end