Directly from the iPhone
When you attach photos in the iPhone Mail app or share them to Mail, iOS usually converts them to JPEG automatically, and Mail offers to reduce the size (Small, Medium, Large, Actual Size). For most recipients Large is enough. Other e-mail apps may attach the original HEIC – if the recipient cannot open it, use the steps below.
From a Mac: convert and reduce
On a Mac (or iPhone) open the converter in Safari, add the photos, choose the E-mail (1600 px) preset and Balanced quality, then download the ZIP. On Windows, convert first with the Photos app (see the guide), then reduce the size with the image compressor, which works in every browser.
Attachment limits
| Gmail | 25 MB per message |
| Outlook.com | 20 MB per message |
| iCloud Mail | 20 MB (larger via Mail Drop) |
The limit applies to the whole message, and attachments grow by about a third when encoded for e-mail. With 1600 px photos you can send roughly 30–60 photos within 20 MB.
Remove the location before sending
Original iPhone photos contain the GPS coordinates of where they were taken. The converter removes them by default, or use Remove Metadata to clean photos without converting them.