Getting an image under 20 KB is one of the tightest limits you'll meet online. It's the band many government and exam application portals reserve for the small signature and passport-photo fields on a form, where the upload box is often capped somewhere around 10–20 KB. This tool compresses a JPG, PNG, or WebP down toward that ceiling entirely in your browser, so the scan of your signature or ID photo never leaves your device.

You set 20 KB as the target and the compressor works toward it automatically: it first lowers JPEG quality, and if that isn't enough it steps the pixel dimensions down as well, since a smaller image simply has fewer pixels to encode. Because 20 KB is so small, the result is best-effort — on a busy, full-colour photo the tool may land a little above or below the exact number rather than hitting 20 KB on the nose.

For form fields that trade-off is usually fine: the reviewer only needs your signature or face to be legible, not print-perfect. If you're specifically shrinking a signature, the dedicated signature tool adds width and height guidance tuned for that use.