GIF Resizer

Most image editors and resizers save only the first frame of a GIF, which kills the animation. This resizer scales every frame of an animated GIF and keeps its timing, loop setting and transparency, so it still plays exactly as before — just at the size you need. Use it to shrink a reaction GIF for a chat app, fit a banner, or make custom emoji and emotes for Discord, Slack or Twitch. It runs in your browser with the ffmpeg engine (about 30 MB, downloaded once); your GIFs are not uploaded.

How to use this tool

1. Choose how to resize: a width or height (the other side follows), a percentage, an exact size, or an emoji/emote preset.
2. For exact sizes and emotes, choose whether the GIF fits inside with transparent margins, fills and crops, or stretches.
3. Pick the number of colours, then choose one or more GIFs.
4. Check the preview and the new size, then download (several GIFs come as one ZIP).

Formula

Keep shape: new height = old height × new width ÷ old width (rounded)

Frames are scaled with the Lanczos filter, which keeps edges crisp when shrinking. Each GIF then gets one palette built from all its frames (ffmpeg palettegen) and only the changed area of each frame is stored, which keeps the file small. Pixels that were transparent stay transparent; GIF transparency is on/off, so soft edges become hard.

Example

A 480 × 270 GIF resized to a width of 320 px becomes 320 × 270 × 320 ÷ 480 = 320 × 180. As a 128 × 128 Discord emoji with "Fit inside", it is scaled by 128 ÷ 480 to 128 × 72 and centred with 28 px of transparent space above and below.

Emoji and emote sizes

Discord and Slack show custom emoji at small sizes, so upload them at 128 × 128; Discord allows animated emoji up to 256 KB and Slack up to 128 KB. Twitch asks for animated emotes at 112, 56 and 28 pixels (up to 1 MB each). If a resized GIF is still too large, choose fewer colours or crop the animation to its subject first.