Free 20KB image compressor
Compress an image to 20KB.
Get a passport-style photo or signature under the size limit of an exam or application form, without uploading it anywhere.
Compress to 20KB
The 20KB target is selected. Change it if your form asks for a different limit.
Drop an image here
JPG, PNG, or WebP · up to 40 MB
1 KB = 1,000 bytes. Target mode may reduce quality and dimensions. PNG has no quality setting. JPG fills transparency with white. Animated images export a single frame. Maximum 40 megapixels and 16,000 pixels per side.
Original size—
Compressed size—
Target check—
Compress a photo or signature to 20KB
- Check the form’s rules. Note the maximum and minimum file size, the format (usually JPG), and any required pixel dimensions.
- Resize first if dimensions are given. Use the Image Resizer to set the exact width and height.
- Compress to 20KB. Drop the image above, keep JPG selected and compress. The target check shows the exact byte count.
- Check legibility. Zoom into the face or signature. If it looks blocky, crop away the background or use a smaller pixel size and compress again.
Typical limits on application forms
Online applications for exams, jobs, visas and government services often set tight limits so that thousands of uploads stay manageable. Signatures commonly have the smallest limit, often between 10KB and 20KB, and photos are often allowed somewhat more. The exact numbers vary between forms and change between years, so treat the notice for your form as the only authority.
| The form says | Set the target to | Then check |
|---|---|---|
| “Maximum 20KB” | 20KB | Result is at most 20,000 bytes |
| “10KB to 20KB” | 20KB | Result is at least 10,000 bytes |
| “20KB to 50KB” | 50KB | Result is at least 20,000 bytes |
| “Less than 100KB” | 100KB | Result is below 100,000 bytes |
Why a 20KB image can look poor, and how to fix it
20KB is very little data for a large camera photo. A 4000 × 3000 phone photo has 12 million pixels; squeezing it into 20,000 bytes forces heavy compression. Cropping to the head and shoulders, or to the signature itself, and resizing to the form’s required dimensions leaves fewer pixels to store, so each one keeps more detail.
For signatures, sign in dark ink on plain white paper and photograph it in even light, then crop tightly. A clean, high-contrast signature compresses far better than one with shadows or a textured background. JPG is usually the right format; PNG can work for a very small black-and-white signature but is rarely accepted for photos.
A file meeting 20KB is not always accepted
Forms also check format, pixel dimensions and sometimes the minimum size. If an upload is rejected, check each requirement in turn. The Image Metadata Viewer shows a file’s exact pixel size and format. If the form wants a different limit, the general image compressor has 50KB and 100KB presets, and the 50KB compression guide covers the process in more depth.
Frequently asked questions
How do I compress an image to 20KB?
Choose your photo or signature. The 20KB target is already selected, so choose JPG and select Compress image. The tool lowers quality first and reduces pixel dimensions only if quality alone cannot reach 20KB. Check the preview, then download.
Is 20KB here 20,000 or 20,480 bytes?
The target check uses 20,000 bytes. Some upload forms count 1 KB as 1,024 bytes, making their limit 20,480 bytes. A file at or below 20,000 bytes meets both definitions.
My form asks for a photo between 20KB and 50KB. What should I do?
Use a target of 50KB instead of 20KB, then check that the result is at least 20,000 bytes. A form with a minimum size can reject a file that is too small, even if it is under the maximum.
Should I resize the image before compressing it?
Yes, if the form specifies pixel dimensions. Resize to the required width and height first, then compress. A smaller image needs less compression, so it keeps more detail at 20KB.
Is my photo or signature uploaded?
No. Compression runs in your browser. Your photo or signature is not sent to SuperUtils, which matters for identity documents and application photos.