Compress images so they send by email
Pick a target size that fits your mail provider, drop the photo in, and download a file that will not bounce.
Sizes use 1 KB = 1,000 bytes, the way most upload forms count, so a "100 KB" result is at most 100,000 bytes.
Drop a JPG, PNG or WebP image here
Compression runs in your browser. The file is not uploaded to a server.
Defaults to 1MB — comfortable for every major mail provider.
Step by step
- Choose a target size. 1 MB per image is safe almost everywhere; drop to 500 KB if you are attaching several.
- Drop the photo into the tool, or click to choose it from your device.
- Look at the before/after slider to confirm the photo still looks right.
- Download the compressed file.
- Attach the downloaded file — not the original — to your email.
- If you are sending more than five photos, compress each one and consider a shared link instead of attachments.
The attachment limits that actually apply
Gmail accepts attachments up to 25MB, Outlook.com up to 20MB, and Yahoo Mail up to 25MB. Those are the headline numbers, but they are rarely the number that matters. Email attachments are Base64-encoded in transit, which inflates them by roughly a third, so a 20MB set of photos arrives as about 27MB of message. Many corporate mail servers cap incoming messages at 10MB or even 5MB, and that cap applies to the inflated size.
The practical rule: keep the whole message under about 8MB and you will never think about it again. For a single photo that means 1MB is generous. For a set of ten, 500KB each keeps you comfortably inside every limit that exists in the wild.
Why the recipient matters more than your provider
Your outbound provider is only half of the journey. A message that Gmail happily sends can still bounce when it reaches a recipient whose employer runs a strict gateway. Bounce messages for oversized attachments are often delayed by hours, so you find out long after you assumed the email arrived.
Compressing before you send removes the entire class of problem. It also makes the email faster to download on a phone with poor signal, which is where most business email is actually read.
How much quality you actually lose
A typical 4MB phone photo compressed to 1MB is, in ordinary viewing, indistinguishable from the original. You are discarding detail that was never visible on a screen. At 500KB the difference becomes findable if you zoom in on textured areas, but it is still comfortably good enough for sharing holiday photos, sending a document scan, or showing a colleague a product shot.
The one case where care is warranted is photos someone will print. Printing needs the pixels, so if the recipient intends to print at anything larger than a postcard, use a file-sharing link and send the original rather than compressing.
What target size to pick
| Situation | Target per image | Why |
|---|---|---|
| One photo, personal email | 1 MB | Looks essentially identical and sends anywhere |
| Three to ten photos | 500 KB | Keeps the whole message under the strictest corporate caps |
| Attaching to a form or ticket system | 200 KB | Helpdesk systems often cap far below mail providers |
| Scanned document or receipt | 200–500 KB | Text stays readable and the file stays small |
| Photo the recipient will print | Do not compress | Send a shared link with the original file instead |
If something goes wrong
Check the total message size, not the individual files. Ten 1MB photos is a 10MB message before Base64 inflation, which pushes it past strict gateways. Compress to 500KB each, or send fewer per message.
That is usually a colour-profile issue rather than compression. Photos saved in a wide-gamut profile can shift when re-encoded. Try the WebP output option, which handles colour more predictably than JPG in browser encoders.
HEIC is an Apple format that Windows and older Android devices often cannot open. Convert to JPG first, then compress. There is a dedicated converter linked below.
Outlook's built-in resize is coarse and applies to every attachment at once, with no preview. Compressing first gives you control over exactly which file the recipient gets.