Slack Emoji & Image Sizes
Slack custom emoji should be 128x128 pixels in PNG or GIF format, under 256 KB. While Slack will resize larger images, uploading at the correct dimensions ensures crisp rendering across desktop and mobile. FastEdit makes it easy to crop, resize, and optimize images for Slack in one click.
Presets
Custom Emoji
128x128 PNG / GIF Max 256 KB
Workspace custom emoji. Square aspect ratio required. Transparent backgrounds are supported with PNG format. GIF emoji can be animated.
Profile Photo
512x512 PNG / JPEG Max 1 MB
Workspace profile picture. Displayed at various sizes in messages, sidebars, and profiles. Square crop recommended.
Tips
- Use PNG with transparency for emoji that need to blend into Slack's message background.
- Keep emoji designs simple with bold shapes: they render as small as 22px in message text.
- Animated GIF emoji are supported but tend to be distracting in busy channels: use sparingly.
- Slack displays profile photos as small as 24px in compact view, so avoid fine detail and small text.