Aseprite to GIF — One Animated GIF per Tag
An .aseprite file keeps each animation as a tag. Drop it here and export "Animated GIF": you get one GIF per tag, named after the tag, with every frame shown for its own duration, the frames lined up on the pivot, and reverse or ping-pong already written out as frame order.
Drop the .aseprite file, open Pack & Export and choose Animated GIF: you get one GIF per tag (hero_walk.gif) with the frames in playback order on one pivot-aligned cell. GIF stores delays in hundredths of a second, so each frame's milliseconds are rounded (125 ms → 130 ms, 16 ms → 20 ms, never below 20 ms); alpha becomes on/off at 128, and up to 255 colours stay exact. It all runs in the browser, without Aseprite installed.
- GIF / APNGDecoded· Pillow
- Godot 4Verified· Godot 4.7.2
- Unity 6Verified· Unity 6000.5.3f1
- Phaser 3 / 4Verified· Phaser 3.90 + 4.2
- PixiJS 8Verified· PixiJS 8.21
- Aseprite JSONVerified· Phaser load.aseprite · PixiJS 8.21
- .asepriteVerified· Aseprite 1.3.18
- Spine / libGDXVerified· spine-canvas 4.2
- Starling / Sparrow XMLVerified· Phaser 4.2
- LÖVEVerified· LÖVE 11.5
- DefoldBuilt· Defold bob.jar 1.13.1
- GameMakerUNVERIFIED
- CSS spritesVerified· Chromium
What a GIF can store, and what an Aseprite frame has
A GIF (GIF89a) is a series of images on one logical screen. Before each image a Graphic Control Extension sets the delay in hundredths of a second, the disposal method (what happens to the image before the next one: 0 not specified, 1 leave it, 2 restore to background, 3 restore to previous) and an optional transparent colour index. Colours come from tables of at most 256 entries. The loop count is not in the GIF89a specification; players read it from the NETSCAPE2.0 application extension.
An Aseprite frame has millisecond timing, 256 levels of alpha per pixel and, in RGBA mode, any number of colours. Converting therefore means three decisions: round the timing to 1/100 s, cut alpha to on/off, and fit the colours into one table. Nerulio writes every frame as a full image with disposal 2, so transparent areas never pile up from one frame to the next.
Very short delays are a trap. WebKit's image decoder plays any frame of 10 ms or less for 100 ms, and its source says this follows Firefox; a delay of 1/100 s can therefore play ten times slower than intended. Nerulio never writes less than 2/100 s (20 ms) and lists how many delays it rounded.
- Delay time
- Hundredths of a second per frame, stored in the Graphic Control Extension: 13 means 130 ms.
- Disposal method
- What the decoder does with a frame before drawing the next. Nerulio writes 2, restore to background, on every full-size frame.
- Transparent index
- One palette entry that is not drawn. Nerulio uses index 0 for every pixel with alpha below 128.
- Loop count
- The NETSCAPE2.0 value; 0 loops forever. Nerulio writes repeat − 1 for a finite repeat and no loop block for a tag that plays once.
Example: what common frame times become
Aseprite frame GIF delay plays as change
125 ms ( 8 fps) 12.5 → 13 /100 s 130 ms +5 ms
100 ms (10 fps) 10 /100 s 100 ms exact
83 ms (12 fps) 8.3 → 8 /100 s 80 ms −3 ms
50 ms (20 fps) 5 /100 s 50 ms exact
33 ms (30 fps) 3.3 → 3 /100 s 30 ms −3 ms
16 ms (60 fps) 1.6 → 2 /100 s 20 ms +4 ms
10 ms 1 → raised to 2 /100 s 20 ms (1 would play as 100 ms in WebKit)
walk 6 × 83 ms = 498 ms in Aseprite → 6 × 80 ms = 480 ms in the GIF
effect 12 × 16 ms = 192 ms at 60 fps → 12 × 20 ms = 240 ms (25 % slower)Frame times that are whole hundredths (10, 20, 30 … ms, so 10, 20, 25 or 50 fps) survive exactly. When the timing must stay to the millisecond, export APNG from the same panel: it stores each delay as a fraction of a second.
What maps to what
| In Aseprite | In Nerulio | In the GIF |
|---|---|---|
| Tag | One animation; a file without tags becomes one animation with every frame | One file per tag, e.g. hero_walk.gif |
| Frame duration (ms) | Kept per frame, rounded on export | Delay in 1/100 s, at least 2 |
| Direction reverse / ping-pong | Playback order written out (ping-pong 0-1-2-3-2-1) | Frames stored in that order |
| Repeat ∞ / n / 1 | Loop forever / n plays / once | Loop count 0 / n − 1 / no loop block |
| Pixel alpha 0–255 | Threshold at 128 | Opaque colour, or the transparent index |
| Colours (RGBA) | ≤ 255: exact; more: median cut over all frames, nearest colour, no dithering | One global colour table |
| Layers, blend modes, opacity | Composited as Aseprite's export draws them | Flat frames |
| Pivot | All frames of the tag on one cell, pivots on the same point | Full-size frames, disposal 2 |
| Slices, hit boxes, user data | Kept in the Studio | Not stored: GIF has no field for them |
What it does
- One GIF per tag, named <file>_<tag>.gif, frames in playback order on one pivot-aligned cell so nothing jumps.
- The tag's repeat count carries over: 0 loops forever, 3 plays three times, 1 plays once.
- Delays are stored in GIF's hundredths of a second. Browsers can show 0 or 1 hundredth as 10 (WebKit does), so the shortest delay written is 2 (20 ms), and the number of rounded delays is reported after export.
- Transparency is one palette entry: alpha 128 and above is opaque, below is transparent. Each frame is a full frame with disposal "restore to background", so transparent frames never pile up.
- Up to 255 colours, which covers almost all pixel art, the palette is exact; above that, median cut over all frames of the tag, nearest colour, no dithering.
How to do it
- Drop the .aseprite file and press Enter to watch each tag on the Timeline.
- Adjust what the GIF should do: a frame's duration in the Frame panel, the direction or repeat in the Animation panel.
- Open Pack & Export and choose Animated GIF, APNG or WebM video.
- Export and read the notes: they list rounded delays, a reduced palette or softened edges, tag by tag.
Files you get
| File | What it is for |
|---|---|
hero_gif.zip | The download, with a folder hero_gif/ (the name follows the export name in Pack & Export). |
hero_gif/hero_walk.gif | The walk tag: its frames, delays and loop count. The frame size is the smallest cell that holds every frame of the tag aligned on its pivot. |
Use the GIF
- Unzip the download. Each tag is its own GIF named after the tag, so rename a tag on the Timeline before export if you want another file name.
- Open the GIF in a browser tab to check the speed: the browser plays the stored delays, so a 6 × 80 ms walk loops every 0.48 s.
- Look at it on the background where it will appear. GIF transparency is on/off: an edge pixel that was 40 % opaque in Aseprite is now fully transparent, one at 60 % fully opaque.
- Where soft edges or exact timing matter, export APNG from the same tags; for a video post, export WebM video (4× nearest) instead.
Check the result
- Count the frames of a ping-pong tag: 4 frames give 6 GIF frames (0-1-2-3-2-1).
- Read the export notes: “n frame delay(s) rounded to GIF's 1/100 s (minimum 20 ms)” tells you which tags changed speed.
- A tag with repeat ×1 stops on its last frame; a tag with ∞ keeps looping.
GIF, APNG or WebM for an Aseprite animation
| Animated GIF | APNG | WebM video | |
|---|---|---|---|
| Transparency | 1-bit (alpha ≥ 128 opaque) | full alpha, exact | none: solid background |
| Colours | exact up to 255, else median cut | every pixel exact | lossy video (VP9, VP8 fallback) |
| Timing | hundredths of a second, at least 20 ms | milliseconds per frame | each frame's own duration |
| Pixel size | 1:1 | 1:1 | 4× nearest-neighbour |
| Files | one per tag | one per tag | one per animation |
| Checked by | Pillow decodes every frame and delay | Pillow, exact frames | Chromium plays it; ffprobe counts the frames |
Troubleshooting
| Symptom | Likely cause | How to check | Fix |
|---|---|---|---|
| Edges look jagged or have a hard halo | GIF has 1-bit transparency: alpha ≥ 128 became opaque, the rest transparent | The export note says semi-transparent pixels were changed | Export APNG for soft edges, or draw the edge with fully opaque pixels in Aseprite |
| The animation is slower or faster than in Aseprite | Delays are rounded to 1/100 s and very short frames are raised to 20 ms | Compare the frame times with the table above; the note counts rounded delays | Use frame times in whole hundredths (10, 20, 25, 50 fps), or export APNG |
| Colour banding or wrong shades | More than 255 colours in the tag, so the palette was reduced by median cut without dithering | The note “More than 255 colours” appears | Reduce the colours in Aseprite (indexed mode) or export APNG |
| The GIF plays once and stops | The tag's repeat is a number (×1 = once) rather than ∞ | Animation panel: Repeat of that tag | Set the repeat to ∞ and export again |
| Only one GIF for the whole file | The file has no tags, so every frame is one animation | Look for tag lanes above the Timeline | Drag tags on the Timeline (or add them in Aseprite) and export again |
Other ways to do it
| Option | When it is the better choice |
|---|---|
Aseprite's own export: File > Export > Export As, or aseprite -b hero.aseprite --save-as hero-{tag}.gif | You have Aseprite and want its options, such as resizing the output; the {tag} form writes one GIF per tag from the command line. |
| APNG from the same export panel | Exact colours, soft alpha and millisecond timing matter more than GIF's reach. APNG is supported by Chrome, Edge, Firefox, Opera and Safari. |
| WebM video | The animation goes into a video post or trailer: enlarged 4× with nearest-neighbour on a solid background. |
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.
| Target | Files | Check |
|---|---|---|
| Godot 4 | .tres SpriteFrames · .tscn AnimatedSprite2D · .png.import | Verified Godot 4.7.2Loaded by Godot; every animation frame drawn and compared with the source file. The scene uses Nearest filtering; rotation is never used. |
| Unity 6 | .unity.json · Editor/NerulioSpriteImporter.cs · AnimationClip | Verified Unity 6000.5.3f1Batch mode: sprite rects, pivots, pixels, clip keys and durations checked. |
| Phaser 3 / 4 | atlas JSON (multiatlas) · .anims.json | Verified Phaser 3.90 + 4.2Frames and animations drawn by both versions. |
| PixiJS 8 | spritesheet JSON · animations · anchor · meta.scale | Verified PixiJS 8.21Rotated and multi-page atlases included. |
| Aseprite JSON | hash / array · frameTags · slices | Verified Phaser load.aseprite · PixiJS 8.21Tags keep their direction and repeat count. |
| .aseprite | layers · tags · durations · slices | Verified Aseprite 1.3.18Opened and rendered by the Aseprite command line. |
| Spine / libGDX | .atlas | Verified spine-canvas 4.2Every region drawn by the Spine runtime, rotated and trimmed; libGDX itself was not run. |
| Starling / Sparrow XML | XML per page | Verified Phaser 4.2Phaser 3.90 draws trimmed XML frames wrongly (its own bug); the "Sparrow XML (Phaser 3)" preset turns trim off and passes in 3.90 and 4.2. |
| LÖVE | Lua quads · nerulio_atlas.lua · main.lua | Verified LÖVE 11.5Every frame drawn and every animation stepped through the shipped helper. |
| Defold | .atlas · .tilesource | Built Defold bob.jar 1.13.1Built by Defold's command-line builder; the built texture's UVs were read back. |
| GameMaker | spr_<name>_stripN.png · gamemaker.json | UNVERIFIEDNot loaded in GameMaker (no headless GameMaker). The strips are cut the way its strip importer cuts them. |
| CSS sprites | .css · preview .html | Verified ChromiumEvery class drawn from the shipped stylesheet. |
| GIF / APNG | one file per animation | Decoded PillowEvery frame and delay decoded again after export; APNG is exact. |
Evidence
GIF decoder: 408 of 408 frames identical to Pillow on 29 real GIFs; APNG 132 of 132 on 16 files. .aseprite: 231 corpus files imported, re-written and reopened in Aseprite 1.3.18 with the same tags, durations and pixels (231/231). Exports: 49 runs in the real engines on real CC0 assets, 47 pass — the 2 failures are Phaser 3.90's trimmed-XML bug, which the Phaser 3 preset avoids.
Limits
- GIF transparency is on/off; Nerulio does not dither or blend edges against a background colour.
- The GIF keeps the sprite's pixel size: the Studio has no scale option for GIF export.
- A grid or island guess is a preview with a confidence; nothing is cut until you press Apply, and every choice has one-click alternatives.
- .aseprite files whose layers do not compose exactly (e.g. group opacity) are imported flattened, and the Import panel says why.
- Rotated frames in an imported atlas stay rotated; their export is UNVERIFIED.
- Images up to 32,768 px per side (268 million pixels), subject to your browser's memory.
Versions and sources
The GIF export was checked by decoding the files with Pillow: every frame and every delay came back as written. The rounding, the 20 ms floor and the alpha threshold are Nerulio's own rules. The GIF structure described here follows the W3C GIF89a specification; the short-delay behaviour comes from WebKit's source; the Aseprite commands from the Aseprite documentation.
Official documentation used
Questions
My GIF edges look jagged, but the Aseprite preview was smooth. Why?
GIF cannot store partial transparency. Pixels at alpha 128 or more are written opaque and the rest transparent, and the export says when that happened. APNG keeps soft alpha exactly and stores delays in milliseconds.
Why does a 16 ms frame play slower in the GIF?
GIF stores hundredths of a second, and browsers can show 0 or 1 hundredth as 10 (WebKit does). The export writes at least 2 hundredths (20 ms) instead and reports how many delays were rounded.
Can I post a bigger version?
The GIF and APNG keep the file's pixel size. The WebM export scales 4× with nearest-neighbour on a solid background, so the pixels stay square in a video player.
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).