The truth about 20KB
20 KB is tiny — roughly a fortieth of a single modern phone photo. There is no setting that squeezes a full-resolution image to 20 KB and keeps it looking good, and any tool that implies otherwise is being optimistic. What actually works is reducing how many pixels the image contains, then compressing what's left.
Do this in order: resize to about 300–400px on the longest side first, then compress to 20 KB. Skipping the resize step is the number-one reason a 20 KB target fails.
Step by step
- Open the image resizer and set the longest side to around 300–400px (smaller for signatures).
- Download the resized image.
- Open the compressor pre-set to 20 KB and add the resized file.
- Click Compress. If it still won't fit, resize a little smaller and try again.
When 20KB makes sense
- Signature-upload fields (often 10–20 KB)
- Some visa and exam registration portals
- Small thumbnail or avatar slots on older systems
- Legacy forms with very low caps
Processing methodBrowser Canvas API
Upload requiredNo
MethodResize, then compress
Last tested4 July 2026
Private by design
Signatures and ID photos are sensitive, so it matters that this never uploads them. The image is read into your browser and compressed there with the Canvas API — nothing is sent anywhere. If 20 KB is stricter than you need, 50 KB gives more room, or set any custom target.