Batch Compressing Photos for Slack Messages
When you have dozens of images, consistency matters as much as size. 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.
Batch Compressing Photos
Drop all the files at once. The same settings are applied to each, so a set of photos for Slack messages ends up with matching dimensions and similar file sizes.
Use Download all to collect everything in one ZIP. A target of 500 KB per image keeps the whole batch predictable.
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
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.
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.
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
- Why Your Images Are Too Large for Slack Messages
If an upload keeps failing, the image is usually larger than it needs to be in more ways than one.
- Image File Size Checklist for Slack Messages
Run through this list before you upload.
- 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.
- Why Your Images Are Too Large for Landing Pages
If an upload keeps failing, the image is usually larger than it needs to be in more ways than one.
- How to Get a JPEG Under 200 KB for Restaurant Menus Online
Hitting an exact size limit is easier with a target-size compressor.