Compress an image to 10 KB — for signatures and tiny uploads

How to use Compress Image to 10 KB

1. Choose one or more images. JPEG, PNG and WebP all work.
2. Check Target size. It is set to 10 KB; you can type another number if the form differs.
3. Leave Save as on JPEG (photos, every form accepts it) unless the form asks for something else.
4. Keep Allow resizing if quality alone cannot reach the target ticked. At 10 KB it is almost always needed for photos.
5. Press Compress to 10 KB. Each file gets a result line with its old and new size, the quality used and the final pixel size.
6. Download the files ending in -10kb.

What it does and when to use it

Ten kilobytes is a very small budget for a picture. Forms set limits this low mostly for signatures, which are dark strokes on white paper and compress far better than photos.

Real cases where you meet it:

• The PAN card signature. The Protean online PAN application asks for a 200 DPI JPEG signature of at most 10 KB (rules checked 2026-10-02). The PAN Card Photo & Signature Resizer has the pixel size built in.
• The lower end of exam windows. SSC and IBPS ask for signatures between 10 and 20 KB. There, 10 KB is the minimum, not the target, so use their own pages.
• Small icons and thumbnails for an old system or an email signature that limits each image.

If you are not sure which size the form wants, read its notice first. Going far under the limit costs quality for no benefit.

How it works

The work happens in a background worker in your browser, using MozJPEG (the jSquash build) for JPEG files.

1. Quality first. The tool tries the image at full size and the highest quality. If that is over 10 KB, it tries quality 30%. If 30% fits, it searches between the two, halving the gap each time, and keeps the best quality that fits.
2. Then pixels. If even 30% quality is over 10 KB, and resizing is allowed, it searches for the largest scale that fits at 30% quality. Then it searches quality again at that new size, so you end up with the sharpest result the budget allows.
3. Limits it respects. It never goes below 30% quality, because blocky artefacts become severe, and never below 5% of the original size.
4. Counting KB. The target is read as 10 × 1,024 = 10,240 bytes. That also satisfies forms that count 1 KB as 1,000 bytes.

Worked examples

These use simple arithmetic: a file’s size in bits divided by its number of pixels tells you how many bits each pixel gets.

A 12-megapixel phone photo (4,000 × 3,000 px). 10,240 bytes is 81,920 bits, which leaves less than 0.01 bits per pixel. No amount of quality reduction gets there, so the tool shrinks the picture until it fits. Expect a final image only a few hundred pixels wide.

A cropped signature, 600 × 200 px. That is 120,000 pixels, so each gets about 0.7 bits. Because most of the area is plain white, which compresses to almost nothing, a clean signature often fits at this size or close to it.

A small passport-style photo, 200 × 230 px. That is 46,000 pixels, roughly 1.8 bits each. This is far more workable than the phone photo above, and a reason to crop and resize to the form’s size before compressing.

Limits and tips

• Crop before you compress. Every bit spent on empty margins is lost to the subject. Trim with the Image Cropper first.
• White really means white. Grey paper, shadows and grain all cost bytes. A clean, evenly lit scan fits more easily.
• PNG is a poor choice at 10 KB. If you pick Same format with a PNG, only the pixel size can change, and the result is often tiny.
• Already under 10 KB? With Same format chosen, the file is left exactly as it was.
• Larger budget available? If the form allows 20 KB, use Compress Image to 20 KB for a noticeably cleaner result.