Compress JPEG 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. The most widely used lossy image format, ideal for photographs and complex images with millions of colors. Use ImageSmith to compress your JPEG images to the ideal file size for Slack — target under 1,000,000KB for optimal performance. Processing is fully browser-based — no server uploads, no privacy risk.
Recommended format
JPEG
Max file size
1,000,000KB
Dimensions
800×600 or smaller for inline chat images
✓Slack generates automatic thumbnails — keep shared images under 1MB
✓PNG for screenshots and diagrams, JPEG for photographs
✓GIFs animate automatically in Slack — keep under 10MB for smooth playback
✓Avoid oversized images in channel history — they slow channel loading