The hell of blocked attachments
We’ve all been there: you try to send photos from an event or scans of work documents, and the axe falls: “Attachment size exceeds the allowed limit.”
Gmail, Outlook and Yahoo enforce a strict per-email limit. Given that a single photo from a recent smartphone easily weighs between 4 and 8 MB, you often can’t attach more than 3 or 4 images per message.
Here’s how to get around the problem without resorting to heavy cloud services like WeTransfer (which route through third-party servers and keep your files for several days).
The real limits by provider (May 2026)
| Provider | Attachment limit | Note |
|---|---|---|
| Gmail | 25 MB | Beyond that, forced upload to Google Drive |
| Outlook.com | 20 MB | 33 MB on the desktop version, but often rejected on the recipient’s side |
| Yahoo Mail | 25 MB | Same as Gmail |
| iCloud Mail | 20 MB | Mail Drop kicks in beyond that |
| AOL Mail | 25 MB | — |
| ProtonMail | 25 MB | Strictest on the free plan |
| Outlook (work) | 20 MB | — |
Tip: the limit shown on the sender’s side is NOT the same as the recipient’s. If you send 23 MB from Gmail to an account capped at 10 MB, the email will be rejected on the recipient’s end.
1. Change the image format (the overlooked trick)
If you’re trying to send screenshots, they’re often saved as BMP or PNG. These formats don’t compress the image (or barely do).
Simply converting a heavy PNG file to standard JPG can cut its size by 80%, without changing its dimensions. A 4K screenshot drops from 8 MB to 800 KB — with no visible change.
Same goes for iPhone photos in HEIC format: converting to JPG not only makes them readable everywhere, but often a bit lighter too (because of the transcoding).
2. Lower the encoding quality
The JPG format lets you adjust the compression level. A photo saved at 100% quality weighs a lot for an imperceptible visual gain. A few concrete reference points:
- 95%: “archival” quality, no visible difference from the original, but a size nearly equivalent to 100%;
- 85%: the sweet spot — imperceptible on screen, size cut by ~2x compared to 100%;
- 75%: difference visible only when zooming to 200%, size cut by ~3x;
- 60% and below: visible, reserve it for thumbnails or drafts.
For a professional email, aiming for 85% offers the best quality/size ratio.
3. Resize the pixel dimensions
A smartphone photo is often more than 4000 pixels wide (ready to be printed on an A2 poster). To be viewed in an email, 1200 to 1600 pixels is plenty — that’s the typical resolution of desktop screens, and well beyond that of mobile screens.
Halving the width divides the file size by ~4 (pixels decrease quadratically). It’s by far the most effective lever.
The fast, private method
Stop wasting time sending yourself 4 different emails.
- Gather your oversized images.
- Drop them into our free local converter.
- Choose “JPG”, set the quality to 85, and check a resize preset of “Web-optimized (max 1200 px)”.
- The tool instantly generates an ultra-light ZIP archive containing all your images, ready to be sent by email.
And the best part? None of your private photos ever left your computer. No detour through WeTransfer or a third-party server. Your ID scans, your medical photos, your confidential work documents stay on your machine.
Frequently asked questions
How many photos can I send in a Gmail email? As many as you want as long as the total stays under 25 MB. With JPGs resized to 1200 px / quality 85, count on 40 to 80 photos per email — vs 3 to 5 photos without optimization.
Does compressing an image degrade quality? Yes, mathematically. But at 85% JPG quality, the degradation is imperceptible in 99% of email use cases.
What if I need to send heavy PDFs? Image compression works on images. For a PDF, use a dedicated tool — but often a heavy PDF contains high-resolution images that can be pre-compressed before re-exporting.
Written by Nikola Markovic · published on May 18, 2026.