Compress an image to 20 KB
A 20 KB limit is what application forms set for signature scans and small photos. Add the image and it is brought under the limit automatically, as a JPG.
- Runs in your browser
- Nothing is uploaded
- No sign-up
- Batch up to 20 images
Drag & drop your image here
or tap to browse · you can also paste from the clipboard
JPG · PNG · WebP · GIF · BMP · AVIF · SVG · up to 50 MB each · up to 20 files
Choose imagesBefore
After
Processed image will appear here.
How to use the 20 KB image compressor
Add your image and download the result: the target is already set to 20 KB and the output to JPG. A signature scan or a small form photo fits at high quality. A larger photo is compressed hard and scaled down, so resize it to the form's pixel size first.
- Add the imageA photo or a scan of your signature. Crop away empty margins first if you can.
- Let it searchThe target is preset to 20 KB, and the result lands just under it.
- Download the JPGThe panel shows the final size, the quality and any scaling that was applied.
About this tool
Twenty kilobytes is a small budget. It comfortably holds a signature scan or a photo a few hundred pixels across, and it is too small for a full-size photograph. That is why the limit appears where it does: on exam, admission and job application forms that want a signature and a small face photo.
This page is the Image File Size Reducer with the target already set to 20 KB and the output set to JPG, the format those forms ask for. It searches the encoder quality for the best result that fits, and scales the image down only if quality alone cannot get there.
What you get
- Target preset to 20 KB, with JPG output
- Finds the highest quality that fits under the limit
- Scales the image down only when quality alone cannot reach 20 KB
- Shows the final size, quality and scale
- Batch up to 20 files and download them as a ZIP
When to use the 20 KB image compressor
Signature for an online application
Forms that ask for a scanned signature usually cap it at 10 to 20 KB. A tightly cropped scan fits with room to spare.
Thumbnail-size applicant photo
Some portals want a face photo only a couple of hundred pixels across, with a matching 20 KB limit.
Avatars on older forums
Message boards with tight attachment limits accept a small square picture at this size.
Thumb impression or initials
Scans of a thumb print or handwritten initials are simple images that compress well below the limit.
What fits in 20 KB
| Image | Size in pixels | What to expect |
|---|---|---|
| Signature scan | about 300 × 100 | Fits at high quality |
| Small form photo | 200 × 230 | Fits at high quality |
| Square avatar | 300 × 300 | Fits with light compression |
| Passport-size photo | 413 × 531 | Fits, with visible compression |
| Phone photo | 4000 × 3000 | Scaled down and compressed hard; resize it first |
How it works
At 20 KB the fixed parts of a JPG start to matter. Every file carries roughly a kilobyte of headers, compression tables and colour-profile data before a single pixel is stored, which is about a twentieth of this budget. The rest has to cover the picture, and a photograph needs around 0.28 bytes per pixel to look clean at quality 80. That works out to roughly 70,000 pixels, or about 300 × 230.
The search lowers quality before it touches the dimensions, and it only scales the image when even the lowest quality setting is too large. For an oversized photo that order produces a picture with more pixels than the budget can describe well, which is why it looks blocky. Giving the tool an image that is already the right size, a few hundred pixels across, lets the same 20 KB go to detail.
Common problems and how to fix them
- The photo looks blocky or smeared
- It has too many pixels for 20 KB. Resize it to the pixel size the form asks for, or to about 300 pixels wide, with the Image Resizer, then compress it here.
- The result is far below 20 KB
- The image is small or plain enough to fit at the highest quality, so there was nothing more to add. This tool only reduces file size. If the form sets a minimum as well, save the image at larger pixel dimensions first.
- The form still rejects the file
- Check its other rules. Many forms also fix the pixel dimensions, the format (usually JPG) and sometimes a minimum size, and reject a file that breaks any one of them.
- My signature has a grey background
- That is the paper as the camera saw it. Photograph the signature in even light on white paper and crop close to the ink. The cleaner the background, the smaller the file.
Frequently asked questions
How do I compress an image to 20 KB?
Add it above. The target is already 20 KB, so the tool searches for the highest quality that fits and gives you a JPG just under the limit.
How do I reduce a signature to 20 KB?
Scan or photograph the signature, crop it close to the ink and add it here. A signature is mostly blank paper, which compresses very well, so it usually fits at high quality with no scaling.
Why does my photo look blocky at 20 KB?
Because 20 KB holds only about 300 × 230 pixels of photograph at good quality. A larger photo has to be compressed hard to fit. Resize it to the dimensions the form asks for first, then compress it here; the result is much cleaner.
The form wants between 10 KB and 20 KB. Will this work?
Usually. The result is the largest file that fits under 20 KB, so a photo lands close to the limit. A very plain image such as a small signature can come out below 10 KB, because this tool only reduces size and never pads a file.
What pixel size fits in 20 KB?
For a photograph, about 300 × 230 pixels at high quality and up to about 440 × 330 with visible compression. Signatures and other simple images fit at much larger sizes, because blank paper costs very little.
Can I compress several files to 20 KB at once?
Yes. Add up to 20 images and press "Process all images". Each one is searched separately against the 20 KB limit, and you can download them together as a ZIP.
Which format should I use for a 20 KB limit?
JPG, unless the form says otherwise. It is what almost every application portal accepts, and it is the default here. WebP keeps more detail at this size, so choose it if the form allows it.