Turn any photo, logo or meme into a 128×128 Slack custom emoji — square, small and with transparency kept. Free, batch friendly, and images never leave your browser (safe for internal screenshots).
Drop your emoji here
PNG · JPEG · WebP · GIF — or paste from clipboard
Slack scales custom emoji down to fit chat, and rejects files that are too large. A square 128×128 export with a small file size uploads cleanly every time — that's exactly what the preset above produces. Discord uses the same 128px box but allows 256KB, so a file Slack refuses may still pass there — see the Discord emoji spec.
In messages your emoji renders at roughly stamp size. Faces, logos and single bold shapes read well; dense screenshots and long text don't. Crop tight to the subject before you drop it here. Making the same art for Twitch or Discord as well? The emote size hub exports every ladder from one upload.
Download the export, then in Slack: click the emoji picker → Add emoji → upload the image and give it a :name:. Workspace admins can allow or restrict who adds custom emoji.
Slack supports animated GIF emoji — drop a GIF and it's resized frame-by-frame with the timing preserved. Keep animations short and simple so the file stays small enough to upload.
Usually the file is too large or not square. Exports from this page are square 128×128 with compressed file sizes, which resolves both of the common rejection reasons.
Yes — resizing happens entirely in your browser. Nothing is uploaded to any server, so inside jokes based on internal screenshots stay internal.
Working across platforms? The hub compares all seven specs side by side and resizes them from a single upload.
Bloggers, mods, and forum members are welcome to share this page. Copy the snippet below to credit the source.
<a href="https://emoteresize.com/slack-emoji-resizer/">Slack Emoji Resizer</a> — free online tool