Upload Errors and File Size Limits for Email Attachments
An upload error is frustrating when the message is vague. Mail providers cap attachment size and big photos slow down both sending and opening, so a lighter file reaches the inbox faster.
Recommended settings for email attachments
| 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.
Upload Errors and File Size Limits
Most errors come from three causes: the file is too big, the dimensions are outside the allowed range, or the format is not accepted.
For email attachments, convert to JPEG, resize to about 1600 pixels and compress below 500 KB. If the form lists its own limits, use those numbers instead.
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 email attachments, 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
- Quick Guide: Compress JPEG for Email Attachments in 30 Seconds
Short on time? Here is the fastest route.
- How to Compress JPEG for Email Attachments
Getting a JPEG ready for email attachments is mostly about two numbers: pixel width and file size.
- Best Image Size for Email Attachments
There is no single magic number, but there is a sensible range for email attachments.
- Best JPEG Quality Setting for Email Attachments
Quality is the slider people touch first, yet it is often the least understood.
- Quick Guide: Compress JPEG for Website Hero Images in 30 Seconds
Short on time? Here is the fastest route.
- Best Image Size for Signature Uploads
There is no single magic number, but there is a sensible range for signature uploads.