Compress Images for Slack
Slack displays images inline in messages and generates previews for shared links. Smaller images load faster in busy channels and improve performance for remote teams. Use ImageSmith to compress your Slack images before sending — free, instant, and entirely in your browser. No account needed, no watermarks, no ads. Target under 1,000,000KB for best results on Slack.
Max size
1,000,000 KB
Format
JPEG
Size
800×600 or smaller for inline chat images
- 1Slack generates automatic thumbnails — keep shared images under 1MB
- 2PNG for screenshots and diagrams, JPEG for photographs
- 3GIFs animate automatically in Slack — keep under 10MB for smooth playback
- 4Avoid oversized images in channel history — they slow channel loading