Resize an image to an exact KB size

Why a KB target is harder than it sounds

Every image editor can make a picture smaller. Very few let you say "the file must weigh between 20 and 50 kilobytes", which is exactly how Indian recruitment portals phrase their rule. The gap matters because file weight is not something you set directly — it is the result of three decisions: how many pixels the image has, how aggressively the JPEG encoder is allowed to throw away detail, and how much noise sits in the picture. Change any one of them and the byte count moves. That is why "resize to 20 KB" usually turns into a guessing game of export, check size, export again.

This tool closes the loop for you. It re-encodes the picture at a series of quality settings, measures the real byte count after each attempt, and keeps narrowing until the result sits inside the window you typed. The search runs on your device, so a dozen attempts cost nothing but a fraction of a second.

The minimum field is the part other tools forget

A rule like 10 KB to 20 KB has two walls. Almost every free resizer only respects the ceiling, which is why so many candidates get "file size too small" after successfully compressing to 6 KB. Signatures suffer the most: a tight crop of black ink on white paper compresses beautifully and lands far below any floor a portal sets.

Here the minimum is a first-class control sitting next to the maximum, not buried in an advanced panel. When a result comes out under the floor, the tool first tries a higher quality setting, then a larger pixel dimension if that is still not enough, and only as a last resort pads the file with harmless metadata. The badge tells you which of those happened, and a separate unpadded download is offered so you can choose the honest file when a portal validates strictly.

Reading the match badge

Green means the file is inside the window with a small safety margin, and the margin is printed next to it so you know how close you are to the edge. Amber means padding was used to clear the minimum. Red means the window itself is impossible for this picture — usually a very large screenshot squeezed under 10 KB — and the fix is to crop or reduce pixels before trying again.

Order of operations that actually works

Pixels first, weight second. If a portal states both a dimension and a KB range, set the dimension in Crop & rotate, then bring the cropped file here. Doing it the other way round wastes effort, because changing pixel size after compression throws the byte count out again.

Formats

JPEG is the right answer for photographs and scanned signatures, and it is what portals expect when they write JPG. PNG stores lossless data, so a photograph saved as PNG can be five times heavier and will fight every KB target you set. Use PNG only for a signature on a transparent background, and convert to JPEG before upload if the form says JPG. WebP is smaller still, but no Indian government portal accepts it yet, so it is not offered as an output here.

A quick sanity check before you upload

Open the finished file and view it at full size. A picture that looks acceptable as a thumbnail can be unrecognisable when a portal enlarges it into a printed admit card, and that is the version a verification desk will see. If the face has gone blotchy, come back and buy quality with a tighter crop rather than a looser target.

Privacy, offline, and why that is not a marketing line

The page loads a small script and does the work with the canvas API. There is no upload endpoint to point at, which is a stronger guarantee than a promise to delete files later. Add the page to your home screen and it keeps working with the data connection off — handy at a cyber cafe with a slow line or in the queue at an exam form counter.