Pixel Art Animation Maker — Frames, Onion Skin, Tags

What it does

• New frame as a copy of the current one (Alt+N) or empty (Alt+Shift+N), delete frames with Alt+C, step with , and . and play or stop with Enter. Tags carry a direction (forward, reverse, ping-pong) and a repeat count.
• Onion skin (F3) shows the previous and next frames under the one you paint, optionally tinted red and blue, with how many of each and their opacity set in the timeline. The preview window (F7) keeps playing the tag at a whole-number zoom while you paint.
• Each frame keeps its own duration in milliseconds, so a held pose and a fast swing can sit in one animation. Playback was measured keeping 100 ms frames on time (20 frames in 2 s) on a 512×512, 100-frame sprite.
• Painting a frame of an imported sheet gives that frame its own pixels; the other frames and the source sheet stay untouched, and the change is one undo step.
• Frames come from anywhere the Sprite workspace reads: a sheet it cuts from its pixels, numbered PNG files, a GIF or APNG with its delays, or an .aseprite file with layers, tags and durations.

How to do it

1. Drop a GIF, numbered frames or an .aseprite file on this page; they arrive as frames and the Pixel workspace opens. A single sheet opens in the Sprite workspace first so its cut can be checked and applied.
2. Select a frame on the timeline, turn on onion skin with F3 and redraw the pose with the neighbouring frames visible.
3. Add in-betweens with Alt+N, type the duration of each frame, and drag across the tag row of the timeline to name the animation.
4. Press Enter or open the preview window with F7 to watch the loop, then save .aseprite or export GIF or APNG per animation in Pack & Export.

Timeline controls while you animate

The same timeline as the Sprite workspace, driven from the Pixel workspace.

Engine exports and how each was checked

"Verified" means the exported files were loaded by the real engine or tool on real CC0 assets and the result was compared with the source. Anything that was not loaded is labelled as such.

Evidence

Cleanup benchmark, 69 CC0 cases with a known 1× original: the exact size found for 81 % (±1 px: 90 %) and 74.0 % of pixels exact with the background kept; the best competitor found 30 % of sizes (perfectPixel) and the best exact-pixel score was 44.6 % (unfake.js). An Aseprite-made ×4 nearest upscale came back 100 % exact and a ×3.78 bilinear resize 99.7 %, both with the size found automatically. A 1 px outline and a drop shadow matched Aseprite pixel for pixel (1846 and 705 px). .aseprite files written here reopen in Aseprite 1.3.18 as indexed, with their layers, blend mode and lock.

Limits

• Not in the Pixel workspace (Aseprite has them): layer groups, linked cels, tilemap layers, reference layers, RotSprite and free rotation or scaling of a selection (only flips and 90°), gradient, spray, contour and text tools, custom brushes (square or round, 1–16 px), tiled drawing, Lua scripting and a command line.
• The symmetry axis is typed, not dragged on the canvas. On touch there is no right button, so the background colour needs the swap button or X.
• Cleanup: JPEG input comes back close (84 % of pixels within ΔE 0.02 with the background kept) but rarely exact (12 %); simulated generated art gets the exact size 20 % of the time (±1 px: 80 %); none of 7 real generated images was snapped automatically — you type the pixel size the panel suggests.
• Indexed conversion picks the nearest colour in Oklab, not Aseprite's RGB distance: 68 % of the test sprite's pixels got a different (perceptually closer) pick. The Lospec search is the only network request and asks first.