How to compress a photo under a KB limit, step by step
Published 6 October 2026
Many forms do not ask for “a smaller photo”. They ask for a photo under a number: 50 KB, 20 KB, 100 KB. A normal photo editor shrinks a file by percentage, which leaves you guessing and trying again. The Compress image to KB tool takes the limit and works backwards from there. The number on your form is yours to read: check your own portal’s current instructions, because limits change and this page cannot tell you what yours is.
The steps
- Open Compress image to KB.
- Choose your photo. JPG, PNG and WebP all work.
- Enter the limit your form asks for in the Maximum file size (KB) field. One KB here is 1,024 bytes, the same unit most file managers show.
- Press Run tool. It tries JPEG quality settings and keeps the best one that still fits under your limit.
- If no quality setting is small enough, it makes the picture smaller, a fifth at a time, and the result tells you the old and new pixel dimensions. Check that against what your form asks for.
- Download the result, then check it with the Document size checker before you upload it anywhere.
What the result is, and is not
The file lands at or below your limit, never at an exact byte count, and the output is always a JPEG. A transparent background turns white. If the limit is too small for the picture, even after shrinking it, the tool shows an error instead of handing back a poor file. In that case, raise the limit if the form allows it, or crop or resize the photo first with the image resizer.
If the result comes out larger than your original file, the tool says so. The limit is a ceiling, so if your original is already under it, you can keep the original.
When the pixel size matters too
Some forms fix the dimensions as well as the file size. This tool may reduce the dimensions to reach your limit, so it is the wrong choice for those. For a signature, use the Signature resizer: it keeps the width and height you give it and squeezes the file to the Maximum JPEG size (KB) you set, and it fails with a message if it cannot do both.
Nothing you choose here leaves your device. The compression runs in your browser, the same as every tool on this site.