Compress an Image to 20 KB

The target below is already set to 20 KB. Drop an image in and the highest quality that still fits is chosen for you — in your browser, with no upload.

Target 20 KB about 550 × 415 pixels for a 4:3 photo, with visible softening on fine detail Nothing uploaded

Drop an image here, or click to browse

JPG, PNG or WebP · processed locally · no size limit

Compressed image preview
Set a size and the quality is chosen for you — the highest that still fits.
80–85 is the sweet spot for photographs. Ignored while a target size is set.
Original—
Compressed—
—
Compression happens in a canvas element on your device. The file is never transmitted, so there is no upload wait and no size cap.

Why people compress to 20 KB

Twenty kilobytes is the tightest limit in common use, and it is almost always an upload form that is asking.

  • Government and examination portals, which often cap uploads at 20–50 KB
  • Older bank or insurance forms with fixed attachment limits
  • Forum and profile avatars
  • Email signatures, where every kilobyte is sent on every message

Can a photo really fit in 20 KB?

This is the one target where something has to give. Twenty kilobytes cannot hold a full-resolution photograph at any quality setting, so the image has to come down in size as well — roughly 550 pixels wide for a typical 4:3 photo. That is fine for a form thumbnail and visibly soft if you print it. The tool drops resolution only after it has exhausted the quality range, so you lose as little as the target allows.

20 KB is often a floor as well as a ceiling

The forms that ask for 20 KB usually ask for a range, and people miss the bottom of it. India's Union Public Service Commission, whose application portal is one of the most-used in the world, states that "Each of the scanned images of the Photograph / Signature should not exceed 300 KB and must not be less than 20 KB in size." Compress below that floor and the upload is rejected just as firmly as one that is too large.

The same instruction pins the pixels at both ends: "The resolution of Photograph and Signature are 350 pixel (Width) * 350 pixel (Height) minimum and 1000 pixel (Width) *1000 pixel (Height) maximum." So the job is not to make the file as small as possible — it is to land inside a window on two axes at once. Check the form for a minimum before you compress, and if there is one, stop when you are comfortably inside it rather than at the smallest file the tool can produce.

Source: UPSC — One Time Registration FAQ

Why 20 KB forces resolution down and larger targets do not

Compression works by discarding detail the eye is poor at noticing, and there is a limit to how much of that any image contains. Past that limit the only remaining lever is to have fewer pixels. A JPEG at a quality setting people find acceptable costs roughly a tenth of a byte per pixel, so 20 KB buys on the order of 200,000 pixels — about 550 across on a 4:3 frame. Ask for the same 20 KB at full resolution and every pixel gets so few bits that the image breaks into blocks.

That is why this tool exhausts the quality range first and only then starts reducing width, re-searching quality at each smaller size. It is also why the honest description of a 20 KB result is soft but legible, rather than the same photograph at a smaller size.

What to photograph if 20 KB is the requirement

Busy detail is what costs bytes: foliage, textured walls, crowds, noise from a dark room. A head-and-shoulders photograph against a plain light background compresses several times better than the same face in front of a bookshelf, because most of the frame is one smooth tone. If you control the photograph and the limit is this tight, a plain background is worth more than any setting in any tool.

How the target is reached

Quality is searched before resolution, because losing a little quality is far less noticeable than losing pixels. The tool encodes your image repeatedly, halving the range each time, until it finds the highest quality setting that still lands under 20 KB. Only if even the lowest quality is too large does it begin scaling the image down, and it re-searches quality at every smaller size rather than simply shrinking until it fits.

One format note worth knowing: PNG is lossless, so a quality setting does nothing to it. Hitting a size target with PNG is possible only by reducing dimensions. For photographs, WebP or JPEG will always get you further.

Frequently asked questions

Drop the file into the box above. The target is already set to 20 KB, so the tool searches for the highest quality that still fits and applies it. Nothing is uploaded — the whole thing runs in your browser.

This is the one target where something has to give. Twenty kilobytes cannot hold a full-resolution photograph at any quality setting, so the image has to come down in size as well — roughly 550 pixels wide for a typical 4:3 photo. That is fine for a form thumbnail and visibly soft if you print it. The tool drops resolution only after it has exhausted the quality range, so you lose as little as the target allows.

At 20 KB you can expect about 550 × 415 pixels for a 4:3 photo, with visible softening on fine detail. The tool always exhausts the quality range before it reduces resolution, so it gives up as little as the target allows.

WebP produces the smallest file at a given quality and is supported by every current browser. Choose JPEG if something specifically requires it, such as an older upload form. PNG is lossless, so a size target can only be met by reducing dimensions — avoid it for photographs.

No. Compression happens in a canvas element on your own device, so the file never leaves your computer. That also means there is no upload wait and no size cap.