GIF Resizer

How to use the gif resizer

1. Choose a GIF; its frames and duration are read out.
2. Set a width or height — the proportions lock together by default.
3. Rebuild and download.

About this tool

Resizing an animated GIF is not the same operation as resizing an image, which is why most image tools return a single still frame when handed one. Every frame has to be decoded, resized and re-encoded with its timing intact.

Scaling down uses box sampling — averaging the source pixels that fall inside each destination pixel — rather than picking one of them. On detailed artwork the difference is stark: nearest-neighbour reduction of a dithered GIF produces noise, because dithering is precisely the pattern that a single-sample reduction turns into speckle. Scaling up uses nearest neighbour deliberately, since a GIF's flat colours and hard edges are usually pixel art, and smoothing those is rarely wanted.

Browsers display animated GIFs and offer no way to read their frames — draw one to a canvas and you get the first frame only. The GIF is therefore decoded by an implementation on this page: header, colour table, LZW-compressed image data, and the disposal model that composes each frame onto the last. That last part is the one usually skipped, and skipping it is why frames come out of some tools with holes in them, since most GIFs store only the pixels that changed between frames.

Rebuilding means re-encoding, and a GIF holds at most 256 colours. The palette is recomputed from frames sampled across the whole animation rather than per frame, because a per-frame palette is larger and makes colours shift visibly as it plays.

Common uses

• Fitting an animation into a size limit for chat or a forum.
• Scaling a screen recording down for a document.
• Making a GIF small enough to email.

Frequently asked questions

Why do other tools return only one frame?

Because drawing a GIF to a canvas gives the first frame only. Anything that edits an animation has to decode every frame itself, which is what happens here.

Will resizing shrink the file?

Usually, substantially — the pixel count falls with the square of the scale. Re-encoding may offset some of it, so the change is reported after rebuilding.

Does the animation keep its timing?

Yes. Each frame keeps its own delay, so the animation plays at the same speed and for the same duration.