Image File Size Checklist for Slack Messages
Run through this list before you upload. Shared images live in workspace storage and get re-downloaded by every viewer, so smaller is kinder to everyone.
Recommended settings for Slack messages
| Setting | Starting point |
|---|---|
| Format | JPEG (WebP where accepted) |
| Width | about 1600 px on the long edge |
| Quality | 78 |
| File size | 500 KB or less |
These are practical defaults. If the platform or form you are using publishes its own limits, follow those instead.
Image File Size Checklist
Is it the right format? Photos should be JPEG or WebP. Is it the right width? Around 1600 pixels suits Slack messages. Is it under the limit? Aim for 500 KB or whatever the destination specifies.
Is it oriented correctly, cropped cleanly and free of private metadata? Our compressor handles orientation and strips metadata automatically when it re-encodes the image.
Step by step with TheCompressJPEG
- Open the compress JPEG to 500 KB tool, or the main compressor for custom settings.
- Drop in your image. Nothing is uploaded; it is processed in your browser.
- Set the maximum width to 1600 and the target size to 500 KB.
- Press Compress, check the result and download it.
Quick tips
- Always keep the original file and compress a copy.
- Use JPEG for photos and PNG for logos and line art.
- Name files descriptively with lowercase words and hyphens.
- Check the result on a phone, where most people will see it.
FAQ
Can I compress images for e-learning courses without uploading them?
Yes. TheCompressJPEG runs entirely in your browser, so your images never leave your device.
Is WebP accepted for e-learning courses?
It depends on the platform. JPEG is the safest choice when you are not sure.
What size should an image be for e-learning courses?
A practical default is about 1600 pixels wide and 200 KB or less, unless the destination states its own limits.
Wrapping up
For Slack messages, the reliable recipe is simple: resize to around 1600 pixels, compress at quality 78 or to a 500 KB target, and check the result before you upload. Keep the original so you can always start again.
Related guides
- How to Get a JPEG Under 500 KB for Slack Messages
Hitting an exact size limit is easier with a target-size compressor.
- Does Compression Affect Image Quality for Slack Messages?
Yes, but how much depends on your settings.
- Fixing Blurry Images After Compressing for Slack Messages
Blurriness after compression usually comes from resizing too far, not from JPEG itself.
- Should You Strip EXIF Data From Images for Slack Messages?
Photos carry hidden metadata such as camera model, date and sometimes GPS location.
- How to Get a JPEG Under 150 KB for Landing Pages
Hitting an exact size limit is easier with a target-size compressor.
- Fixing Blurry Images After Compressing for Restaurant Menus Online
Blurriness after compression usually comes from resizing too far, not from JPEG itself.