Compress images for email attachments

Email · 2025-02-03 · 5 min read

Every email provider has an attachment limit: Gmail 25 MB, Outlook 20 MB, iCloud 20 MB, Yahoo 25 MB. Crossing the limit gets your email rejected — sometimes silently. The fastest fix is compression.

Email limits at a glance

• Gmail: 25 MB outgoing, 50 MB incoming.
• Outlook / Office 365: 20 MB outgoing.
• Apple Mail / iCloud: 20 MB outgoing (5 GB via Mail Drop link).
• Yahoo: 25 MB outgoing.
• ProtonMail: 25 MB outgoing.

The single best workflow

For most email attachments, this 4-step workflow gets you under any limit in under a minute:

1. Open shrink44.com/reduce-file-size.
2. Drop your image or PDF.
3. Type a target size of 20 MB (safely under Outlook's limit).
4. Click Compress, attach the result.

For photo attachments specifically

1. Open Compress JPG.
2. Set quality to 78%.
3. Cap longest side to 1920px (looks great on any laptop screen).
4. Bulk-drop multiple photos for a single ZIP.

For PDF attachments

PDFs are the usual culprit at work — scanned contracts, brochures, receipts. Use Compress PDF with Medium quality. Typical result: a 28 MB scanned PDF becomes 4–7 MB.

Why not zip the attachment?

ZIP-ing images and PDFs gives almost no size cut — those formats are already compressed. Recompressing the source is far more effective.

Privacy bonus

Because Shrink44 runs entirely in your browser, your contracts, passports, IDs, medical reports and other sensitive attachments are never uploaded to a third-party server. That's the right architecture for documents you wouldn't want indexed or logged.