Tools

Resize to 20 KB

Drop an image to make it 20 KBAdd an image to make it 20 KB

Get photos, scans and signatures under 20 KB, with the pixel size it took.

or paste with CtrlV JPG, PNG, WebP, AVIF, GIF or BMP

Your files never leave your device

About this tool

Resize an image to 20 KB without guessing

To get an image under 20 KB, drop it here and press Compress. ToolHero tries quality first and shrinks the pixels only when even quality 40 is too big. Our 12 MP test photo came out at 374×499 pixels and 19,991 bytes; a signature shrank only to 1446×603. Nothing leaves your device.

What 20 KB did to our test files

Three files from our own test set, each compressed once with the settings this page opens with.

  • 12 MP phone photo 3024×4032, 5.17 MB → 374×499 at quality 42 19,991 bytes
  • A4 form scanned at 300 dpi 2480×3508, 3.22 MB → 445×630 at quality 51 19,573 bytes
  • Signature on white paper 1800×750 PNG, 167 KB → 1446×603 at quality 41 19,877 bytes

Tested with MozJPEG via @jsquash/jpeg 1.6.0 (mozjpeg 3.3.1) and Lanczos3 resizing via @jsquash/resize 2.1.1; Mac18,5 (Apple M6), macOS 27.0.1; 2026-10-13. Chromium, WebKit and Firefox gave byte-identical files.

The trade a 20 KB limit forces

Twenty kilobytes is one of the tightest limits a website can set, and our 12 MP test photo starts about 250 times larger. Something has to give. Turning the quality down until the file fits is the old trick, and it wrecks faces and text long before it gets there.

So ToolHero stops lowering quality at 40, the point where photos still look like photos, and takes the rest out of the pixel count instead. A 12 MP shot keeps about 1.5% of its pixels: plenty for a small portrait on a screen, too few for a print.

Can a scanned page be read at 20 KB?

Just about. A full A4 page squeezed into 20 KB ends up roughly 445 pixels wide, which is about 54 pixels per inch of paper. Headings, printed labels and ticked boxes stay legible on a screen; small print and handwriting blur.

  • Crop to the part that matters. A form that only needs the signed section reads far better when you crop to it first in Crop, then come back and compress.
  • One page per file. If the site takes several files, send each page on its own instead of a combined image.
  • Scan in greyscale or black and white. Fewer colours leave more of the 20 KB for detail.

Signatures and stamps fit easily

Ink on white paper is cheap to store: almost every pixel is the same white. Our test signature kept 80% of its width at 20 KB, so the strokes stay crisp. Scan or photograph it on plain paper in good light, crop close around it, and it fits with room to spare.

How it works

  1. Add the image

    Drop a photo, scan or signature here, or choose it from your device. A batch works too.

  2. Keep the settings

    JPG, a 20 KB target and Allow smaller dimensions are already on. Press Compress.

  3. Check the size, then save

    Each file lists its final size in bytes and the pixel size it was shrunk to. Download one, or all of them as a .zip.

Is 20 KB 20,000 bytes or 20,480?

It depends on who counts. Most sites and operating systems now treat a kilobyte as 1,000 bytes; some older systems use 1,024, a kibibyte. We aim at or under 20,000 bytes, which passes both rules, so a file we label 19.99 KB is accepted either way.

Questions, answered

Why did my photo come out so small in pixels?

Because 20 KB is tiny for a photo. Rather than drop the quality to a point where the picture falls apart, ToolHero keeps it at 40 or above and reduces the pixel count until the file fits. The new size shows on the file and in its steps.

Can I keep the full pixel size and still hit 20 KB?

Usually not with a camera photo. Turn off Allow smaller dimensions and ToolHero keeps the size, goes down to quality 40, and tells you if the file still couldn’t reach 20 KB. Crop the photo first if you need more detail where it counts.

What happens to a JPG that is already below 20 KB?

You never get a bigger file back. If saving it again at the default quality would make it larger than your original, the original is handed back untouched.

Will a website that wants 20 KB accept a file of 19.99 KB?

Yes: anything at or under the limit passes, and ours stay under it whether the site counts 1,000 or 1,024 bytes to the kilobyte. If a site also sets a minimum, try the KB range page instead.

Is the 20 KB copy made on a server?

No. The image is decoded, resized and saved by code running in your browser tab, so it never travels over the internet.

Other sizes

Everything happens on your device, so your files never leave your computer or phone.

JPG · ≤ 20 KB

Format

Opens everywhere. No transparency.

Compression

We find the highest quality that fits, and shrink the image only if it still doesn’t.

When even the lowest quality is too big, the image is scaled down until it fits.

Add images to compress them