How to compress a photo or signature to 20 KB, 50 KB or 100 KB

Updated 15 October 2026 · 2 min read · FreeAIConverters guides

Application portals for jobs, university admissions, exams, passports and banks often require a photo between 20 and 50 KB and a signature under 20 KB, sometimes with exact pixel dimensions too. A phone photo is usually 2–5 MB, about 100 times too big.

The fastest way

1. Open Compress Image to KB.
2. Choose your photo or scanned signature.
3. Type the target size from the form, for example 50 KB. Use a number a little below the maximum, such as 45 for a 50 KB limit.
4. Download the JPG and upload it to the form.

If the form also asks for dimensions

Many forms say something like "200 × 230 pixels" or "3.5 × 4.5 cm". First use Resize Image or Crop Image to get the right shape and size, then compress to KB. Cropping first also makes the face bigger in the frame, which looks better at small sizes.

For passport-style photos, the Passport Photo Maker crops to the right proportions with a face guide.

Signatures

• Sign with a black or dark blue pen on plain white paper.
• Photograph it in daylight and crop tightly around the signature.
• Compress to the required size; signatures stay crisp even at 10–15 KB.

Common errors and fixes

• "Invalid file format": the form probably wants JPG. Convert with PNG to JPG or HEIC to JPG for iPhone photos.
• "File too small": some forms have a minimum (e.g. 10 KB). Aim for the middle of the allowed range.
• Blurry result: reduce the pixel size first; a small sharp image beats a big blurry one at the same KB.