How to Compress Images for Email Attachments (Under 1 MB)
Email clients handle images differently from browsers. Some strip them, some block them by default, and many impose strict size limits. Sending large attachments can trigger spam filters, slow down inboxes, and annoy recipients. This guide shows you how to compress images for email so they land cleanly every time.
Why Image Size Matters in Email
- Attachment limits: Gmail allows 25 MB total per message. Outlook is 20 MB. Many corporate mail servers cap at 10 MB.
- Spam scores: Large or numerous attachments raise spam filter scores.
- Mobile recipients: Downloading a 5 MB email attachment on mobile data is slow and expensive for the recipient.
- Inbox storage: Sending many large images quickly fills your recipients' mailboxes.
The 1 MB Rule
As a general rule, keep each image attachment under 1 MB. For a professional email with multiple images, keep the total under 5 MB. For newsletters, images embedded via URL (hosted externally) are better than attachments.
Email Client Format Support
| Client | JPEG | PNG | WebP | AVIF |
|---|---|---|---|---|
| Gmail (web) | ✅ | ✅ | ✅ | ❌ |
| Outlook (Windows) | ✅ | ✅ | ❌ | ❌ |
| Apple Mail (macOS/iOS) | ✅ | ✅ | ✅ | ✅ |
| Thunderbird | ✅ | ✅ | ✅ | ❌ |
| Corporate Exchange | ✅ | ✅ | ❌ | ❌ |
Conclusion: Always use JPEG for email attachments and inline images to ensure maximum compatibility, especially with Outlook and corporate servers.
Recommended Settings by Use Case
Photos sent to family / friends
- Max width: 1600 px
- Quality: 75–80%
- Expected output size: 100–300 KB per photo
Professional client photos (high quality required)
- Max width: 2048 px
- Quality: 85–90%
- Expected output size: 300–700 KB per photo
Product images for e-commerce emails
- Max width: 800 px
- Quality: 75%
- Expected output size: 50–150 KB per image
Newsletter / HTML email inline images
- Host images externally (S3, CDN, or your server) and link via URL — do not attach
- Max width: 600 px (standard email column width)
- Quality: 72–75%
Step-by-Step with JPEGMinify
- Open JPEGMinify.
- In Settings, set Max Width to
1600(or your target dimension). - Set Quality to
78. - Leave Output Format as JPEG for maximum email compatibility.
- Drop your photos into the drop zone. Batch compress multiple attachments at once.
- Review the comparison slider — original vs compressed.
- Click Download All as ZIP, unzip, and attach the JPEG files to your email.
All processing happens in your browser. Your photos are never uploaded to any server — important for confidential client work, legal documents with images, or personal family photos.
Stripping EXIF Metadata
JPEGMinify automatically strips EXIF metadata (GPS location, camera model, shooting date) when re-encoding with MozJPEG. This is a free privacy benefit — you won't accidentally share your home location when emailing a photo taken near your house.
What About Sharing Many Photos?
For large albums (10+ photos), consider using a sharing link (Google Photos, iCloud, Dropbox) instead of direct attachments. Use JPEGMinify to compress before uploading to those services as well — it speeds up the upload and reduces storage usage.