Email signature image too large: shrink to 50 KB

Email signature or logo image too large? Shrink it to 50 KB

Images in an email signature are sent with every message, so a heavy one makes each email bigger and can slow how mail opens. Some mail systems also reject signatures that are too large.

Nothing is uploaded. Your browser does the compression, so the file stays on your device.

Lands under the real limit. We aim a little below it, so the upload goes through first time.

Fast. A 30 second 1080p clip fits into 10 MB in about two seconds on a desktop.

When you need 50 KB

A logo on a flat background compresses very well. A photo should be small, around 150 to 300 pixels wide.

What to expect

A small headshot or flat logo stays clear at 50 KB. Use PNG only if you need transparency.

How big a picture fits in 50 KB

Rough pixel sizes at good quality. The tool checks the real result, so treat these as a guide.

What it is	About this many pixels
Detailed photo (landscape, crowd)	400 x 270
Typical photo or headshot	490 x 330
Scan, signature or screenshot of text	850 x 570

How we hit the number

We try the highest quality that fits. If the picture still will not fit even at a lower quality, we reduce the pixel size a step at a time until it does. Photos are saved as JPEG by default, which every form accepts. You can switch to WebP or PNG with the format menu.

The target we aim for is 49 KB, which is 2 KB under 50 KB, so the file is not turned away over a few bytes.

Questions people ask

Is 50 KB a rule?

No, it is a sensible target we picked, not a platform limit. Use the exact size box for a different number.

JPEG or PNG?

JPEG for photos, PNG for flat logos that need transparency.

Limits change. We link the official page wherever there is one, and the safety margin means a small change is unlikely to matter. Last updated 2026-11-09.