Slack emoji resizer
Slack emoji size is 128x128 pixels: Slack shrinks bigger uploads to that. Stills of any size go in, but a GIF still over 128 KB after the shrink is refused. Drop a GIF or image here to get a square file under 128 KB, animation kept.
How to resize an emoji for Slack
- Drop an animated GIF, PNG, JPG, or WebP into the box above. Until you do, the tool shows a sample GIF that starts over every Slack limit.
- Pick the size (128 px is the usual one) and whether to fit the whole image or crop it to a square.
- The tool resizes every frame and re-encodes the GIF until it is under 128 KB. The checklist shows the size, frame count, and file size.
- Download the file. In Slack, open the emoji picker in the message box or the status dialog and click Add Emoji at the bottom. Upload the file and paste the name the tool suggests.
Frequently asked questions
What size should a Slack emoji be?
Slack stores custom emoji at 128x128 pixels, so make it square and 128x128. We uploaded 11 test files to a real workspace on 2026-09-30: a 2000x2000 PNG and a 3 MB PNG were both accepted and stored at 128x128, and a 300x100 PNG was padded to a square with transparency. Emoji show at 32 pixels or smaller in messages, so a bigger image looks the same.
What is the Slack emoji GIF size limit?
A GIF has to be under 128 KB after Slack shrinks it to 128x128. A 512 px, 134 KB GIF went in at 71 KB, but a 277 KB GIF that was already 128 px failed with "This image is a bit too big, even after resizing." The help center says 50 frames, yet 60- and 150-frame GIFs went in with every frame. This tool keeps 50 to stay inside the documented limit.
How do I resize a GIF for Slack without losing the animation?
Drop it in the resizer above. It decodes every frame, scales each one to the size you pick, and writes a new animated GIF. If the source has more than 50 frames, it keeps 50 spread across the clip and adds the skipped frames' time to their neighbors, so one loop lasts as long as before.
How does the tool get a GIF under 128 KB?
It tries the cheapest cut first. It lowers the color count, then the pixel size, and then keeps every second frame. In clips without transparency, frames after the first only store the pixels that changed, which cut a test clip from 281 KB to 185 KB. The result line shows which settings it used.
Why does Slack say my emoji file is too big?
The file is over 128 KB. Phone photos and screen recordings often run to several megabytes, so resize them first. A 128x128 PNG is almost always under the limit. Long or noisy GIFs are the ones that need fewer colors or a smaller size.
Is this Slack emoji resizer free, and is my file uploaded?
It is free with no account or watermark. Decoding, resizing, and encoding run in your browser, so the file never leaves your computer.
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