Compress a photo to 20 KB — small ID photos and signatures

How to use Compress Image to 20 KB

1. Pick your photo or scan, or several at once.
2. The Target size box already says 20 KB. Change it only if your form gives a different number.
3. Under Save as, JPEG is the safe choice for forms. WebP is smaller but fewer portals accept it.
4. Allow resizing if quality alone cannot reach the target is ticked by default. Untick it only if the pixel size must not change.
5. Select Compress to 20 KB and read each result line: before and after size, quality and pixel size.
6. Save the new files, which end in -20kb.

What it does and when to use it

Twenty kilobytes sits between “signature only” and “real photo”. At the small pixel sizes that ID forms use, it is enough for a recognisable face, and it gives a signature room for smooth, clean strokes.

You will meet it in places like these (rules checked on 2026-10-02 from each body’s own notice):

• PAN card photo. The Protean online PAN application asks for a colour JPEG photo of at most 20 KB at 200 DPI. Its exact pixel size is built into the PAN Card Photo & Signature Resizer.
• Bank and SSC signatures. IBPS and SSC both want the signature between 10 and 20 KB. A file here must also stay above 10 KB, so their dedicated pages, such as the SSC Signature Resizer, are the better fit.
• Small profile pictures on older intranets, school portals or ticketing systems.

How it works

Your images never leave the browser tab. A background worker decodes each one and encodes it with MozJPEG for JPEG, or the browser’s own WebP encoder.

The tool looks for the highest-quality file that fits:

• Step 1, full size. Try the top quality. If it is 20 KB or less, keep it.
• Step 2, quality search. Otherwise try 30% quality. If that fits, search between 30% and the top, halving the gap seven times, and keep the best that fits.
• Step 3, smaller pixels. If 30% is still too big and resizing is allowed, find the largest size that fits at 30%, then search the quality again at that size.

The target is 20 × 1,024 = 20,480 bytes, so the file also passes portals that count 1 KB as 1,000 bytes.

Worked examples

A quick sum explains most results: multiply the KB by 8,192 to get bits, then divide by the number of pixels.

A PAN-size photo, 197 × 276 px. That is 54,372 pixels. 20 KB gives 163,840 bits, about 3 bits per pixel. At this size there is no need to resize, and the tool can usually keep a high quality.

A square 1,000 × 1,000 px profile picture. A million pixels share the same 163,840 bits, about 0.16 bits each. That is very little. Expect the tool to shrink it, and make sure it is cropped to the face first so the face is not tiny.

A signature cropped to 900 × 300 px. 270,000 pixels, about 0.6 bits each. Because most of a signature is blank paper, this often fits with only a small drop in quality.

Limits and tips

• Shrink to the form’s size first. If the form names pixels, resizing to them before compressing gives a much sharper face than letting the tool scale down a huge photo.
• Plain backgrounds help. A white or light wall costs very few bytes compared with a patterned curtain.
• Minimums matter. Some forms reject files under a minimum, such as 10 KB. Check the rules for both ends.
• One limit for a batch. Every file in a batch gets the same target. Do photos and signatures in separate runs if their limits differ.
• Need even smaller? Use Compress Image to 10 KB. Have more room? Compress Image to 30 KB keeps more detail.