Hitting Gmail's 25MB attachment limit on a long email thread is an oddly modern frustration. Phone cameras now produce 5–10MB photos by default, so even four or five images is enough to bounce a message. The good news: compressing them down to a perfectly readable size takes about 30 seconds. Here's how.
Email attachment limits, in one place
- Gmail: 25MB per message (uses Google Drive for larger files automatically).
- Outlook / Microsoft 365: typically 20MB to 25MB, depending on the admin's settings.
- Apple Mail / iCloud: 20MB by default; up to 5GB via Mail Drop.
- Yahoo Mail: 25MB per message.
Worth knowing: the "real" limit is usually the recipient's server, not yours. A 24MB email might leave Gmail fine and bounce off the recipient's corporate Outlook with no useful error. Compressing to a comfortable 5–10MB total is the safest choice.
How small "email-friendly" really needs to be
For images that just need to be looked at on a screen, around 500KB to 1MB per image is plenty. That gives you roughly 25 to 50 photos per email comfortably under any provider's limit. For documents that will be printed, aim slightly higher (1–2MB per image) and avoid going below 1500px on the long edge.
The fastest way: drop them into a browser tool
For a small number of files, our free online image compressor will get the job done in seconds. Drop the photo in, wait a moment, download the smaller version. Your image never gets uploaded anywhere — compression happens in your browser — which matters if you're sending sensitive content like contracts, medical records or photos of documents.
Repeat for each image, then attach the compressed versions to your email instead of the originals.
What about resizing?
For email-only use, you can be even more aggressive than usual. Most email is read on a phone or laptop screen, so 1280px on the long edge is plenty. Anything bigger is pure attachment weight. Our compressor caps at 1920px by default, which is already excellent for email — but if you want to go smaller, most desktop operating systems include a built-in resize tool too:
- Mac: Open in Preview → Tools → Adjust Size.
- Windows: Right-click → Resize pictures (in Windows 11), or open in Photos → Resize.
For large batches: send a link instead
If you're sharing more than 20 photos, even compressed, the right move is usually a link rather than attachments. Free options:
- Google Drive: any file in your Drive can be shared via "Get link".
- WeTransfer: 2GB free, no account needed.
- Apple iCloud Mail Drop: built into Mail on Mac and iPhone, up to 5GB.
Even with a link, it's worth compressing first if the images are going to be viewed on screens — your recipient's download will be faster and their phone will thank you.
Compressing screenshots for email
Screenshots from a Mac save as PNG by default, which is the right format for sharp UI but also the largest. A long Mac screenshot can hit 5MB easily. Compressing PNG screenshots is just as quick: drop the file into the same image compressor and it'll re-encode the PNG with smarter compression. Expect 60–80% savings.
Tip: if the screenshot has text in it, stay with PNG and avoid converting to JPG — JPG's lossy compression makes text edges fuzzy.
Privacy reminder
Photos straight from a phone often contain location and timestamp metadata. Most online compressors — including ours — strip metadata as a side effect of re-encoding the file. That's usually a plus when you're sending images to someone you don't know well, like an estate agent, recruiter or insurance adjuster.
The 30-second workflow
- Open our image compressor in a new tab.
- Drop the photo in.
- Click "Download compressed image".
- Repeat for each photo, attach all compressed versions to your email, and send.
That's it. The whole flow takes roughly 30 seconds per image and reliably gets you under any provider's attachment cap.