Reduce photo size for email

The cap applies to the whole message

Personal Gmail allows 25 MB in total attachments. Outlook.com also lists a 25 MB attachment limit. Work or school accounts may have limits set by an administrator; check the product and account you actually use.

Above its attachment limit, Gmail replaces attachments with a Google Drive link. Check sharing permissions and whether the recipient allows links. If the instructions require a file attachment, prepare a smaller file or agree on another delivery method.

Attachment limits and message encoding

Base64 transport encoding can add about one third to binary data. That matters when a server limits the encoded message. Personal Gmail’s published 25 MB allowance is for attachments, so do not derive a universal 18 MB photo limit from it. Read the actual rejection notice before reducing images further.

Check the destination mailbox

The sender's attachment allowance and the recipient's message policy are separate checks. Read the rejection notice for the limit that actually failed. A corporate or university mailbox does not have a universal 10 MB cap.

Ask the recipient for its limit or an approved delivery alternative before repeatedly reducing the photo. If this is a document upload rather than email, follow that field's format and pixel requirements too.

Resize first, then compress

For photos viewed on a screen, a 1920 px long side is one possible starting point, not an email requirement. Keep the requested resolution for printing or documents. Tinolia accepts images up to 32 megapixels; export a smaller copy in another app first if the original exceeds that input limit.

Then run Compress image on the result. Doing it in that order matters: a quality slider applied to a 4000 px JPEG still leaves a heavy file, because the pixels were never the part you needed.

1. Open Resize image and set the long side around 1920 px, keeping the ratio.
2. Run that JPEG through Compress image. Up to 10 files, 20 MB each.
3. Attach the downloaded files, watch the total the compose window shows.

HEIC and WebP in the attachment

iPhone photos are usually HEIC. Gmail on a Mac may preview them, while Outlook on Windows shows a generic icon, which reads like a size problem and is not one. Convert with HEIC to JPG first.

A file Chrome saved can be WebP even when the URL said .jpg, and it gets refused the same way: Chrome WebP. If you send this kind of album every week, the camera setting is worth reading: iPhone JPEG.

What the mail app offers on its own

Apple Mail can downsize on send, offering Small, Medium, or Large. That smaller copy exists only in that message, and the roll on your phone stays exactly as heavy as before.

If your mail app offers smaller image sizes, inspect the attached copy before sending. A 4K screenshot may need a different approach to protect small text: PNG too large.

When a cap means a different format

If they asked for a specific number rather than just smaller, the KB pages are more direct: Compress to 200 KB or Compress to 500 KB. A 50 KB portal field is its own job: 50 KB photo.

And if what they really want is one file to read rather than twelve attachments, a single PDF is easier on everyone: iPhone to PDF. Chat quality loss is the opposite problem: WhatsApp original.

A JPEG under 50 KB

Upload pattern.jpg to the 50 KB tool. The cap is 51,200 bytes: 50 × 1,024.

A JPEG under 50 KB

File and format	Dimensions / pages	Bytes
Inputpattern.jpg	800 × 600 px	488,899
Outputtarget-50kb.jpg	424 × 318 px	47,431

Input

Output

The output is below the cap, and the engine also reduces the pixel dimensions. A file fitting the byte limit can still fail a form with a minimum width or height. Check both conditions.

Try Compress to 50 KB with the sample

Measurements apply to these files and settings, not to every upload. The engine version and processing environment can change the bytes. The public examples stay available; your uploads follow the 24-hour deletion policy.