Compress Image to 20KB
Compress an image to 20KB online free for signatures and ID photos. Works with JPG, PNG and WebP, and runs in your browser: nothing is uploaded.
Drag & drop images here
Everything happens in your browser: your images are never uploaded anywhere. You can also just paste (Ctrl/Cmd+V) an image or an image URL.
MonsterConvert lowers quality as little as it can to get the file at or under this size.
Resize first (optional)
Some forms ask for a pixel size as well as a file size. Set it here and the file size is fitted after resizing.
How to compress a image to 20KB
Three steps, all in your browser.
Add your image
Drag and drop a JPG, PNG, or WebP file, click to browse, or paste it from your clipboard.
Check the 20KB target
The target is already set to 20KB. Change it, or pick a different output format, if you need to.
Compress and download
Click Compress and download a file at 20KB or under, with as much quality kept as possible.
When you need 20KB
20KB is the limit many application forms set for signatures and small ID or passport-style photos. At this size the image is usually a small, tightly cropped picture, so it helps to crop first and let the compressor shrink the rest.
What to expect at 20KB
As a rough guide, a typical photo at 20KB is about 330 x 250 px as a JPG, but only about 100 x 80 px as a PNG, because PNG keeps every pixel without loss. Logos, screenshots, and drawings with flat colors fit far more.
Tips for getting to 20KB
- Crop tightly first. A signature or ID photo only needs the subject, and every cropped pixel is bytes saved.
- Use a plain, evenly lit background: flat areas compress far better than textures.
- For a signature, use dark ink on white paper and photograph it in good light. A noisy, shadowy scan is what pushes it past 20KB.
Nothing uploaded
Compression happens in your browser using WebAssembly, so your photos and documents never touch a server.
Highest quality that fits
Instead of guessing a quality setting, it searches for the best one that keeps the file at 20KB or under.
Batch friendly
Drop in several images at once and compress them all to the same size in one go.
Related tools
Get the file ready first
Compress by quality instead
Frequently asked questions
Drop your image into the box above and click Compress. MonsterConvert searches for the highest quality that still keeps the file at 20KB or under, and only shrinks the pixel dimensions if the quality alone can't get there. Then download the result.
It will be 20KB or smaller, as close to it as the search can get, which keeps as much quality as possible. It won't be padded up to the exact size. If your image is already under 20KB, it is returned unchanged.
Very large or very detailed images sometimes can't get under a small target without shrinking a lot. When that happens the row tells you it got as close as it could instead of pretending it hit the target. Try cropping away unneeded parts first, or set a larger target size.
Leave it on Auto for most cases. JPG and WebP files stay in their own format. PNG, BMP and ICO files are converted to JPG, or to WebP if they contain transparency, because those formats can't be squeezed by lowering quality. Choose JPG when a form asks for JPG, or PNG if you must keep it (PNG can only get smaller by reducing the pixel size).
Photograph or scan it on plain white paper in good light, crop closely around it, and compress it here. A tightly cropped signature a few hundred pixels wide fits in 20KB with room to spare.
20KB is a very small budget, so some detail has to go. The compressor lowers pixel size only as much as needed. Cropping to the face or the field the form asks for keeps the useful detail sharper.
Yes. Open "Resize first (optional)" under the size controls and set a fixed width, exact dimensions, or a percentage. The image is resized first, and the file size is then fitted to 20KB.
MonsterConvert uses 1 KB = 1,000 bytes, so the result stays under the limit whether a website counts a kilobyte as 1,000 or 1,024 bytes. The size shown next to your file uses the 1,024 convention, so it can look slightly lower than 20KB.
No. The image is compressed inside your browser using WebAssembly, so it never leaves your device. That makes it safe for ID photos and other private documents.
Yes. Turn on "Keep original dimensions" under the size controls. Only the quality changes then, so the image may end up a little over 20KB if the quality floor isn't enough.