Pixel Art Cleanup — Remove Anti-Aliasing and Stray Pixels
Everything is reported as candidates first — highlighted on the image and counted — and changed only when you tick it. The anti-alias remover snaps each in-between pixel to one of the two palette colours it sits between.
- PNG framesMeasured· Pillow
- PaletteMeasured· re-import
- pixel-lab.jsonUNVERIFIED
What it does
- Anti-alias remover: a pixel between two palette colours snaps to the nearer end of that pair; decisions read the original pixels, so scan order cannot change the result.
- Stray pixels, tiny clusters (size adjustable) and single-pixel holes from one component scan.
- Outline checks: gaps, doubled runs and thickness on straight edges; the auto-fix only closes gaps.
- Alpha is untouched unless you set a cut-off, and then only rounded to 0 or 255.
How to do it
- Drop the frames.
- Read the candidate counts and look at the highlighted pixels.
- Tick the fixes you want (anti-alias, strays, clusters, holes, outline gaps).
- Export the cleaned frames.
Outputs and how each was checked
"Measured" means the downloaded file was opened again outside the page (Pillow, numpy or an independent parser) and the property was measured. Loading these files in a game engine was not tested.
| Target | Files | Check |
|---|---|---|
| PNG frames | anim_N.png · 1×–8× nearest | Measured PillowEvery exported colour re-read from the PNGs lies inside the locked palette. |
| Palette | .gpl · .hex (Lospec) · .json | Measured re-importEach format was exported and imported back through the UI: 16 → 16 colours. |
| pixel-lab.json | generic frames + palette | UNVERIFIEDGeneric JSON; not loaded in any engine. |
Evidence
8 anti-aliased frames → one 16-colour palette with 0 exported colours outside it; an unchanged region identical in all 8 frames with dithering off and with Bayer 4×4; the anti-alias remover took 271 colours to 16 without moving a single silhouette pixel; integer scale, offset and 2.5× non-integer scaling detected exactly.
Limits
- Frames larger than 4096 × 4096 are refused: every pass runs on the main thread, and there is no cancel button yet.
- A sprite sheet is treated as one image; cut it into frames first (sprite sheet cutter).
- With a dithering mode on, the cleanup counts include dither pixels; set dithering to None first.
- The exported JSON is generic; importing it into Godot or Unity was not tested.
Questions
Will it move my sprite's outline?
No. On the test frames the anti-alias remover changed 0 alpha pixels while taking 271 colours down to the 16 of the palette.
Does it work on dithered art?
Dither patterns are made of single pixels, so the counts include them; set dithering to None before cleaning.
Is it free, and do I need an account?
Everything on these pages is free and works without an account. There is no watermark and no export that is held back.
Are my sprites uploaded?
No. The Studio decodes, packs and exports in this browser tab. Projects are autosaved in the browser (IndexedDB) and can be saved as a .nerulio file.
Does it need Aseprite or an engine plugin installed?
No. .aseprite files are read and written in the browser, and each engine bundle carries what that engine needs (for Godot, the import settings and scene; for Unity and the Godot TileSet, a small editor script).