Signatures for digital forms
Signature Under 10 KB — 140×60 px
Preset and ready: drop a file and the output lands under 10 KB as JPEG, capped at 140×60 px — processed entirely in your browser.
Drop your image here or browse
JPEG, PNG, WebP — iPhone HEIC tips inside — processed entirely in your browser
Why this exact limit matters
Scanned signatures are awkward files: a black-on-white scan from a phone produces an image that is far larger than the tiny limits forms allow, yet the signature itself has almost no visual complexity. Size limits that look brutal for photos are usually easy for signatures.
A signature is high-contrast line art, which compresses extremely well — hitting a small kilobyte target normally costs almost nothing in legibility. 10 KB is one of the tightest limits you will meet online, and this page is preset to exactly that ceiling.
This page locks both constraints for you: the output is capped at 140×60 px and at 10 KB total size, which is the combination application forms actually check.
How to compress to 10 KB
- Drop your signature scan into the box above — it stays on your device.
- Confirm the target: under 10 KB as JPEG, dimensions set to at most 140×60 px.
- The MozJPEG encoder searches its quality range so the JPEG output lands just under your limit. Dimensions are set to at most 140×60 px.
- Preview the result, compare it with the original if you want, and download — the filename carries its actual size.
Tip: If your scan has a grey or shaded background, the encoder spends bytes on that noise. A clean white background is the single biggest size saver for signature files.
Frequently asked questions
Should my signature be PNG or JPEG?
JPEG is accepted by virtually every form and reaches very small sizes on line art. If you need PNG specifically, this tool optimizes it losslessly and offers a JPEG alternative when the lossless result cannot fit your limit.
Why JPEG and not another format for my upload?
JPEG is the most universally accepted image format on upload forms and gives the smallest files for photographs. If your destination accepts only "images", JPEG is the safe choice.
Do I need an account or app install?
No account, no install, no watermark. The page you are on is the whole tool.