How to Compress Image for Email Attachment

Sending large image files by email is one of the most common causes of bounced messages, slow delivery, and frustrated recipients. Most email providers — including Gmail, Outlook, and Apple Mail — have a maximum attachment size of 10–25MB. But even when your file fits within the limit, sending a 10MB image when a 300KB one would work just as well is poor etiquette.

Recommended Image Sizes for Email

For images shared by email, the general rule is to keep individual images under 1MB, and ideally under 500KB. If you're sending multiple images, keep the total email size under 10MB to ensure reliable delivery across all email providers and corporate mail servers.

How to Compress Images for Email

1. Open the Image Compressor at imgresizr.com.
2. Upload your image (JPG, PNG, or WebP).
3. Set the quality to 75–80% — this removes imperceptible data while maintaining a sharp appearance on screen.
4. Download the compressed image and check the file size before attaching to your email.
5. If still too large, reduce dimensions first using the Image Resizer, then recompress.

Email Image Best Practices

Resize Before Compressing

A smartphone photo is often 4000×3000px — far larger than any monitor can display. Resize to 1920×1080px or smaller before compressing. This single step can reduce file size by 70–80% before you've even touched the quality setting.

Use a Sharing Link for Large Sets

If you need to share 10+ photos or very high-resolution originals, use Google Drive, Dropbox, or WeTransfer. Upload the full-resolution files there and share a link in the email. This avoids any attachment limits and ensures the recipient gets the best quality version.