Image Attachment Size Limits for Every App

Image attachment size limits are the maximum file sizes each app lets you send. Go over the limit and your email bounces, or the app refuses to attach the picture. This is why a few high-resolution photos can be surprisingly hard to share.

This guide lists the current limits for email, messaging apps, and work tools in one place, explains why your image is often bigger than it looks, and shows what to do when a file is too large to send.

Image attachment size limits by app

Here are the current image and file size limits for the apps people use most.

Numbers change over time, so treat these as a guide and check the app if you are close to the edge.

Email attachment limits

Email is where size limits bite most often, since it was never built for big files.

Most providers hold attachments to 20 to 25 MB:

• Gmail: 25 MB

• Outlook: 20 MB, with larger files sent as a OneDrive link

• Yahoo Mail: 25 MB

• iCloud Mail: 20 MB

There is a catch, though. Email has to turn attachments into text to send them, and that step adds about a third to the size. So a 20 MB photo can weigh around 27 MB on the way out, which pushes it past a 25 MB limit. To stay safe, keep your real file under about 18 MB.

If the file is bigger, most email apps offer to upload it to their cloud and send a link instead. That link has no size limit.

Messaging app limits

Messaging apps are more generous than email, but they have their own habits.

WhatsApp. You can send documents up to 2 GB, which sounds huge. The catch is that photos sent the normal way get compressed automatically, so they lose quality. To keep a photo sharp, send it as a document instead of as a photo.

Telegram. Also 2 GB, and it keeps full quality. Telegram is one of the best options for sending a large, sharp image without fuss.

Facebook Messenger. Around 25 MB for a file. Photos are compressed like on most social apps.

iMessage. Roughly 100 MB, and it handles photos and videos well between Apple devices.

The pattern to remember: many chat apps quietly shrink your photos to save data. If quality matters, send the image as a file or a document, or share a link to the original.

Chat and work tool limits

Team tools are built to share files, so their limits are higher, but they still vary.

Slack. Up to 1 GB per file, which is plenty for any image. On the free plan, the limit is your total storage, not the size of a single upload.

Discord. This one depends on your plan:

• Free: 10 MB per file.

• Nitro Basic: 50 MB.

• Nitro: 500 MB.

A large screenshot can pass the free 10 MB limit fast, which is why many people share a link on Discord instead.

Microsoft Teams. Around 250 MB per file, enough for high-resolution images and short clips.

For everyday screenshots, all three are fine. The limits only get in the way with very large images or long recordings.

Why your image is bigger than you think

A single screenshot can be tiny, or it can be several megabytes. A few things decide the size.

Resolution. More pixels means a bigger file. A screenshot from a 4K monitor holds four times the pixels of a 1080p one, so it weighs much more.

Format. A PNG keeps every pixel and stays sharp, but it is large. The same image as a JPG or WebP can be a fraction of the size.

Detail. A busy photo with lots of colors is harder to compress than a plain screenshot, so it ends up heavier.

Email encoding. As covered above, email adds about a third to a file's size when it sends it, so the real limit is lower than the number you see.

This is why a shot that looks small on screen can still bounce from an email. If you keep hitting limits, a smaller format like JPG or WebP, or a lower resolution, usually solves it.

Check the size before you hit send

Knowing the number saves the bounce. On Windows, right-click the file and open Properties. On a Mac, select it and press Cmd+I. On a phone, the photo's info panel usually shows the size. As a rough guide, phone photos run 2 to 5 MB, full-screen screenshots land between a few hundred KB and 2 MB, and anything scanned or exported from an editor can be far larger. If the number is anywhere near the app's cap, skip the attachment and send a link, which weighs nothing in the message no matter how large the image is.

What to do when your image is over the limit

If a file is too big to send, you have a few options.

Compress it. Save the image as a JPG or WebP instead of a PNG. For a photo, that alone can cut the size by more than half with little visible change.

Resize it. Lower the resolution. If a screenshot is 4K but only needs to be read on a phone, a smaller version looks the same and weighs far less.

Crop it. Trim to just the part that matters. A tighter image is a smaller image.

Share a link instead. This is the simplest fix for a large file. Upload the image once and send a short link, which has no size limit and keeps full quality. It works in any email or chat. For the steps, see our guide on how to turn an image into a URL.

For a one-off small image, compressing or resizing is fine. For anything large, or when quality matters, a link avoids the limit entirely.

Conclusion

Every app draws its own line, from 25 MB on email to a gigabyte on Slack, and email quietly makes that line lower than it looks. Knowing the numbers saves you a bounced message or a compressed, blurry photo.

When a file fits, send it as it is. When it does not, compress it, resize it, or upload it once and share a link. A link sidesteps the limit completely and keeps your image at full quality, wherever you send it.