Your photo is too large to email
Attachment limits are smaller than phone photos. The fix is usually dimensions rather than quality and it takes one pass.
A modern phone photo is between 8 and 25 megapixels. A dozen of them won’t fit in an email and the usual response, dragging the quality slider to the floor, produces small files that look awful.
Fix the dimensions first
This is the lever nobody reaches for and it does most of the work. Halving the width of an image quarters the number of pixels in it. A 4000 pixel wide photo has sixteen times the pixels of a 1000 pixel one.
Ask what the photo is for. Viewed on a phone or in an email body, 1600 pixels wide is more than enough. Printed at 6 by 4 inches, 1800 by 1200 is plenty. Going above that is sending detail nobody will see.
Cap the width, then look at the size. Most of the time you’re already under the limit and the quality slider never has to move.
Then the format
If the photos are HEIC from an iPhone and the recipient is on Windows, convert them and you’ll find the JPGs are larger than the HEICs were. That is normal and capping the width covers it.
If you control both ends, WebP is a quarter smaller than JPG at the same quality, though it is worth checking the recipient can open it before relying on that.
Quality last
At quality 85 a photograph is visually identical to the original for practical purposes. At 75 it is still hard to tell apart. Below 60 you start seeing halos around edges and banding in smooth areas like skies.
The order matters because compression and dimensions multiply. Cutting the dimensions first means the same quality setting produces a much smaller file, since there is less image to describe.
What not to bother with
Zipping. Compressed data does not compress again. A zip of twenty JPGs is about the size of twenty JPGs.
Converting to PNG. It is lossless, so a photograph gets larger, often much larger.
Sending the originals “just in case”. If the recipient actually needs full resolution, a link or a shared folder is the right tool, not a mail server.
For a related next step see Why won’t a website accept my photo?.
Common questions
What is the actual attachment limit?
Gmail and most providers cap a message at around 25MB and the encoding attachments use inflates them by roughly a third, so the practical limit is nearer 18MB of actual files. Corporate mail servers are frequently stricter, often 10MB.
Will the recipient notice the difference?
Not if you resize rather than crush the quality. A photo capped at 2000 pixels wide and saved at quality 85 looks identical on any screen it’ll be viewed on and is a fraction of the original size.
Can I just zip the photos?
It’ll not help. JPG and HEIC are already compressed and zipping compressed data saves almost nothing, typically one or two percent. Zipping is useful for keeping a batch tidy, not for making it smaller.
What about sending a link instead?
It is the right answer for a genuinely large set and most mail clients now offer it automatically past the limit. The trade is that the recipient needs to be able to reach that service, which isn’t always true for corporate or government addresses.