You're trying to attach a few photos to an email. Gmail bounces it. Outlook says the attachment is too large. Or the email goes through but takes three minutes to send and the recipient can't open it on their phone.
Modern smartphone cameras produce images that are 6–12 MB each. Gmail's attachment limit is 25 MB. That's two or three photos — and one of those "you've photographed a multi-page document" situations can hit the limit with a single email.
Email attachment size limits (the actual numbers)
- Gmail: 25 MB per email (combined attachments). Files over 25 MB are automatically converted to Google Drive links.
- Outlook / Hotmail: 20 MB for most accounts. Microsoft 365 business accounts may allow more.
- Apple Mail (iCloud): 20 MB, with a Mail Drop option that sends larger files via iCloud link.
- Yahoo Mail: 25 MB.
- Corporate email servers: Often stricter — 10 MB is common, sometimes as low as 5 MB. When in doubt, keep attachments under 10 MB.
Why phone photos are so large
A 12-megapixel photo taken on a typical iPhone or Android phone is 4032×3024 pixels. Uncompressed, that's about 35 MB of raw image data. JPEG compression brings it down to 4–8 MB depending on the scene complexity. That's still a lot for an email where the recipient is just going to look at it on their screen — screens display at 72–96 PPI, so a 4000-pixel-wide image is only being shown at 1000 pixels wide anyway.
You can cut that 6 MB photo to under 500 KB at quality 75 without any noticeable loss at normal viewing sizes. For document photos that just need to be readable, you can go even lower.
The right approach by situation
A few photos to share casually
Gmail and Apple Mail have built-in "resize before sending" prompts — Gmail will ask you if you want to shrink large attachments; Apple Mail's share sheet offers size options. Use these. They're convenient, they work, and the quality is fine for casual sharing.
Document photos that need to remain readable
For photos of contracts, IDs, receipts, or handwritten notes: readability matters more than colour accuracy. The Compress Image for Email tool gives you a quality slider — use the Balanced setting, which targets around 75–80% quality. The result is sharp enough to read clearly and small enough to attach comfortably.
Multiple documents that need to be one file
If you're sending multiple pages of a document and want to avoid a pile of separate attachments, convert to PDF first using the Images to PDF tool, then check the resulting file size. If the PDF is still too large, compress the images first before converting.
What not to do
- Don't screenshot the photo to compress it. Screenshots go through additional JPEG recompression and often end up larger, not smaller. They also crop the image to your screen size.
- Don't use WhatsApp as a pass-through. Sending via WhatsApp and downloading from there does compress the image, but WhatsApp's compression is aggressive and loses quality faster than a proper compressor at equivalent file sizes.
- Don't just rename a PNG to JPG. Changing the file extension doesn't change the format or the file size. The file needs to actually be re-encoded.
A note on PNG files
PNG uses lossless compression, which means it's often several times larger than an equivalent JPEG for photographs. If someone sends you a large PNG photo that you need to re-send, converting it to JPEG at quality 80 is the fastest size reduction available — often cutting the file to a quarter of its original size with no perceptible difference.