Slack Emoji ConverterAny image,
Slack-sized.
Crop a square, get a crisp 128×128 PNG or animated GIF under 128 KB, ready to upload as a custom Slack emoji.
- Free, no signup
- Runs in your browser
- Keeps transparency & animation
Drop an image here
Select a filePNG, JPEG, WebP, AVIF, BMP or GIF · max 10 MB
From picture to emoji in four moves
Drop an image
PNG, JPEG, WebP, AVIF, BMP or GIF, up to 10 MB. Drop it in or select a file.
Frame your square
Move and resize the square to choose the part of the image you want.
Generate and check
Click Generate, check the preview on light and dark backgrounds, then download the PNG or GIF.
Add it to Slack
In Slack, open the emoji picker, choose Add Emoji, upload the file and name it.
Slack emoji size and requirements
A Slack custom emoji is a square image of 128 × 128 pixels that weighs 128 KB or less. This converter produces exactly that.
Read the full requirements| Dimensions | 128 × 128 pixels (square) |
|---|---|
| File size | 128 KB or less |
| File types | PNG, JPG or GIF (animated GIFs work) |
| Name | Lowercase, no spaces: letters, numbers, dashes, underscores |
| This tool accepts | PNG, JPEG, WebP, AVIF, BMP and GIF, up to 10 MB |
| Animation | Kept as a GIF, reduced to 50 frames at most to fit 128 KB |
Last updated:
Your image never leaves your browser.
There is no server and no upload. The crop, resize and compression all happen on your device, and nothing is stored once you close the tab.
Questions, answered
What size should a Slack emoji be?
Slack custom emojis are 128 × 128 pixels and must weigh 128 KB or less. This tool crops your image to a square, resizes it to 128 × 128 px and makes sure the PNG or GIF stays under the limit.
Which image formats can I convert?
PNG, JPEG, WebP, AVIF, BMP and GIF. Static images become a PNG, which keeps transparency; animated GIFs stay animated GIFs. SVG, HEIC and TIFF files are not supported yet.
Is my image uploaded to a server?
No. The conversion runs entirely in your browser: your image never leaves your device and nothing is stored.
Can I make an animated emoji?
Yes. Drop an animated GIF and you get an animated GIF back: the crop applies to every frame and the loop is kept. Slack allows at most 50 frames and 128 KB, so longer or heavier animations are automatically reduced (fewer colours, then fewer frames, then a smaller size). If it still does not fit, you are told so.
How do I add the emoji to Slack?
In Slack, open the emoji picker, choose Add Emoji, upload the file, give it a name and save. Your workspace settings may limit who is allowed to add emojis.