Guide
How to Compress Photos for Email (Gmail, Outlook & Forms)
Email is where oversized photos cause the most daily friction: slow sends, bounced messages, and recipients who never open a 20 MB attachment. Here is the size math, and how to hit it.
The size rules that actually matter
- Per photo: 100-500 KB. Sharp enough on any screen, instant to load on mobile data.
- Per message: stay under 10 MB total. Gmail and Outlook cap messages at 25 MB, but the effective limit is lower once attachments are base64-encoded (~37% overhead).
- Corporate filters: many reject or quarantine messages over 10 MB regardless of provider limits.
Why "just attach the original" fails
A 4 MB phone photo × 6 photos = 24 MB — over Gmail's cap before you have written a word. And some clients offer to "shrink" attachments, but you do not control the result. Compressing before attaching keeps the quality decision with you.
The two-minute routine
Resize to at most 1600 px wide (Image Resizer), then compress to your target — Compress Image for Email targets a phone-friendly ~500 KB per photo, or use 100KB / 200KB pages for tighter limits. The result attaches instantly and looks identical on any screen.
One more trick: send as document
WhatsApp-style apps re-compress photos sent as photos. Email does not, which means a clean compressed JPG arrives exactly as you saved it — no double-compression artifacts. More size context in the main file-size guide and the JPG-specific guide.
People also ask
What is the best photo size for email?
100-500 KB per photo, under 10 MB per message. That loads instantly on mobile and clears every major provider's limits with room to spare.
Does Gmail compress my photo attachments?
Gmail offers to shrink oversized attachments, but you do not control the result. Compress to your own target before attaching and the quality stays your decision.
JPG or PNG for email photos?
JPG for anything photographic — it is several times smaller at the same visual quality. PNG only for screenshots and graphics with text.