The published limits
| Service | Attachment limit | What happens over it |
|---|---|---|
| Gmail | 25 MB | Google states that Gmail automatically removes the attachment and adds it as a Google Drive link. |
| Outlook.com | 25 MB | Microsoft states that the attachment size limit for files is 25 MB, and directs larger files to OneDrive, which accepts up to 2 GB. |
| Work or school mailbox | Set by the administrator | Often 10 MB or 20 MB. The message bounces with a server error rather than converting to a link. |
The receiving server has its own ceiling, and the lower of the two wins. A message that leaves your outbox can still bounce at the far end.
Why 25 MB is not 25 MB
Mail carries binary attachments as text, using an encoding that grows the payload by roughly a third. A 24 MB file becomes about 32 MB on the wire and fails a 25 MB check. Plan for about 18 MB of real files against a 25 MB ceiling and the arithmetic stops surprising you.
Modern phone photos make this easy to hit. A 48-megapixel capture lands between 5 MB and 15 MB. Four of them clear the limit before you have written the message.
Pick a sensible target
- 200 KB to 500 KB for viewing on a screen Fine on a phone or a laptop. Twenty photos at 400 KB come to 8 MB, which fits any mailbox.
- 1 MB to 2 MB when detail matters Enough for someone to zoom in on a document photo or a damage report without straining.
- Full resolution for printing Do not compress. Share a link instead, because a printed A4 needs the pixels a 500 KB file no longer has.
Compress to a ceiling in four steps
- Open the compressor Load the image compressor and choose one still JPEG, PNG, or WebP up to 50 MB.
- Choose JPEG or WebP output A file-size ceiling needs a lossy encoder. PNG output here is a lossless re-encode and often does not shrink at all.
- Set Maximum file size Type the number and pick KB or MB. The tool reads decimal bytes, so 500 KB means 500,000 bytes, and it echoes the exact byte count before it starts.
- Check the result, then download The reported size is the measured size of the real output file. Compare the before and after view at full size, then save.
When no tested quality reaches your ceiling, the photo simply holds more detail than the target can carry. Reduce the width in the image resizer first, then set the ceiling again. Fewer pixels is the honest way to reach a small file.
A compressed copy also travels lighter
The compressed file does not carry over supported EXIF, GPS, XMP, IPTC, origin, or C2PA records. That means the copy you attach usually holds no coordinates, no capture time, and no camera serial, which matters when the recipient is an insurance adjuster, a landlord, or a stranger on a marketplace.
When you want that removal on its own, without touching the image quality, use the metadata remover. It deletes the fields and leaves the encoded pixels byte-identical.
Email attachment FAQ
What is the Gmail attachment size limit?
Gmail accepts attachments up to 25 MB. Google's help page states that when a file goes over the limit, Gmail automatically removes the attachment and adds it as a Google Drive link instead.
What is the Outlook attachment size limit?
Microsoft's help page for Outlook.com states that the attachment size limit for files is 25 MB, and points you to OneDrive for files up to 2 GB. A work or school mailbox may enforce a lower ceiling set by the administrator.
Why does my email bounce when I am under the limit?
Mail systems encode attachments for transport, and the encoding adds roughly a third to the raw size. A 25 MB ceiling therefore accepts about 18 to 20 MB of actual files. The recipient's server may also enforce a smaller limit than yours.
How small should a photo be for email?
For reading on a screen, 200 KB to 500 KB per photo looks fine and lets you attach dozens. For printing, keep the full resolution and send a link instead.
Does compressing remove the photo's metadata?
The compressed copy does not carry over supported EXIF, GPS, XMP, IPTC, origin, or C2PA records. Vaultaire scans the output to confirm, though it cannot rule out every proprietary or pixel-embedded signal.
Can I compress several photos at once?
The tool takes one file at a time so every result stays measured and verified. For a set of photos, repeat the steps. Each pass runs in a second or two.