Make an image exactly 20 KB
- 20 KB is already selected. Add your JPG or PNG.
- Download it: the new file is exactly 20 KB (20480 bytes), with the same picture, width and height.
- Upload it to your form.
When a 20 KB minimum trips you up
Forms that ask for a signature or a small passport-style photo at a minimum of 20 KB reject smaller files, even when the image is perfectly clear. A signature scanned at 300 DPI and cropped tightly is often only 5–15 KB, below a 20 KB minimum. Re-scanning or enlarging the image changes it; this tool instead adds a hidden comment to the file so it reaches 20 KB while the image stays identical.
Check the other rules too
- Maximum size: if the form says “20–40 KB”, any size in between is fine; choose a value like 30 KB with the custom size option.
- Pixel size: some forms want a fixed width and height in pixels; this tool doesn’t change them.
- DPI: if 300 DPI is required as well, run the file through convert to 300 DPI first.
Frequently asked questions
How can an image be made bigger in KB without changing it?
JPEG and PNG files can hold comments that viewers ignore. The tool adds a hidden comment of exactly the right length, so the file reaches the size you need while the picture stays bit-for-bit the same.
Why do forms need a minimum file size?
Many exam, job and government forms set a minimum, for example a photo of 20–50 KB and a signature of 10–20 KB, to block blank or tiny images. If your photo is 12 KB, the upload is rejected even though it looks fine.
Will the form accept it?
The file is a normal, valid JPG or PNG of the size you chose, with the same width and height. Check the form’s other rules too (dimensions in pixels, format), as they are separate from the file size.
Can it make the file smaller too?
No, this tool only increases the size. If your image is already bigger than the target, it is left as it is.
Are my images uploaded?
No. The files are edited in your browser, so they never leave your device.
Last updated 2026-10-24.