Your three PDFs total 22 MB on disk, and a 25 MB limit rejects the email. Why?

Encoding for email makes them about a third bigger in transit 22 MB × 1.33 is about 29 MB, over the limit.

What usually saves the most space when emailing phone photos?

Reducing the pixel dimensions Fewer pixels means much less data; quality changes save less.

You need to send a fillable PDF form that's too big. Which choice keeps it usable?

Compress PDF in Balanced mode, or share a link Balanced keeps form fields; a link avoids changing the file.

Module 5: Forms, uploads and file-size limitsLesson 25 of 255 min read

Email attachment size limits: Gmail, Outlook, iCloud and Yahoo

An email with a few phone photos or a scanned contract can bounce or refuse to send, even when the files seem modest. Each service sets a maximum message size, the receiver's has one too, and attachments grow on the way. Here are the main limits as the providers state them, and how to get under them.

The limits, service by service

Work and school accounts can differ, because an administrator sets them.

Gmail (personal accounts): 25 MB for all attachments together; anything larger is added as a Google Drive link.
Outlook.com: 25 MB for the whole email, text included. OneDrive links don't count, and a linked file can be up to 2 GB.
Yahoo Mail: all attachments in one message, sent or received, must not exceed 25 MB.
iCloud Mail Drop: attachments up to 5 GB, which expire after 30 days and don't count towards your iCloud storage (there is a 1 TB Mail Drop limit).

The receiver matters too

Your message must fit the receiver's limit too; Yahoo applies its 25 MB to incoming mail. If unsure, stay well under 20 MB.

Why attachments grow in transit

Attachments travel encoded as Base64, which turns binary data into plain characters. Microsoft's Exchange documentation states that this increases the message size by approximately 33 percent.

So files just under a limit can still be refused: the server may measure the encoded message, not the files on your disk.

What a limit leaves for files

Microsoft's own example: a server limit of 64 MB allows a realistic message of about 48 MB, because 64 ÷ 1.33 ≈ 48. Applied the same way, a 25 MB limit measured after encoding leaves about 25 ÷ 1.33 ≈ 18.8 MB of actual files.

Photos: fewer pixels, then compression

A phone photo often holds more pixels than a screen shows. Reducing the pixel count is the biggest saving; lowering the JPEG quality a little saves more. The lesson on image compression explains the trade-off.

The Batch image processor's Photos for email recipe saves each photo as a JPG of 2048 px and under 500 KB. It keeps the date taken and removes the location.

Ten photos

Ten photos at 500 KB make 5 MB; with a third added for encoding, under 7 MB, inside every limit above.

PDFs: compress and combine

Compress PDF has two modes. Balanced re-saves the photos inside and keeps text, links and form fields working. Strong turns each page into an image for the biggest saving, but text can no longer be selected. If the result isn't smaller, the original is kept. The guide on why PDFs get big has more.

For several scans, combine them into one PDF with JPG to PDF or Merge PDF: easier for the receiver, and compressed once.

When to share a link instead

Some things shouldn't be squeezed: a video, original photos for printing, or a document that must stay exactly as it is. Send a link instead: Gmail adds a Drive link above 25 MB, Outlook.com can share from OneDrive, and iCloud has Mail Drop.

A link means the file sits on a cloud service, so think about who can open it and for how long.

Check before you send

Add up the sizes and allow a third for encoding. Check one photo and one PDF page at full size, and keep the originals until everything has arrived.

Shrink a heavy PDF before you attach it, or use the Batch image processor's Photos for email recipe for a set of photos.

Compress PDF

Quick check

Three questions. Pick an answer to see why.

Your three PDFs total 22 MB on disk, and a 25 MB limit rejects the email. Why?
Show the answer
Answer: Encoding for email makes them about a third bigger in transit 22 MB × 1.33 is about 29 MB, over the limit.
What usually saves the most space when emailing phone photos?
Show the answer
Answer: Reducing the pixel dimensions Fewer pixels means much less data; quality changes save less.
You need to send a fillable PDF form that's too big. Which choice keeps it usable?
Show the answer
Answer: Compress PDF in Balanced mode, or share a link Balanced keeps form fields; a link avoids changing the file.

Rules change

File formats and official photo rules change. Each guide shows the date it was last checked; for forms and official photos, the authority's own page has the final word.

Sources

Last checked October 27, 2026

Free tools for files you have the right to use. Everything runs on your device; check important results (forms, prints, official photos) before you send them. Terms of use.