Free Compress Image to 20KB
The form says the file is too large. What it is really asking for
A 20 KB limit is tiny. It is roughly one hundred and fifty to two hundred times smaller than a typical phone photo, which weighs somewhere between 3 and 5 MB. When a portal rejects your upload with a vague message, it is not being fussy. Some older systems really do store thousands of small images in a fixed amount of space, so they cap every file hard, and nobody ever went back to raise the number.
The good news is that a 20 KB picture of a face or a signature can still look perfectly usable, as long as it is cropped well and saved in the right format. This tool does the squeezing. You do the cropping.
A quick sense of scale
It helps to picture what 20 KB actually is. A plain text email with no pictures, about three and a half thousand words long, is around 20 KB. So you are being asked to fit a whole picture in the space of a long email. That sounds impossible until you remember that a small image does not need much: a 300 pixel wide photo has under a hundred thousand pixels, and good compression stores them far more cheaply than the raw numbers suggest.
It also explains why how big the picture is in pixels matters more than anything else here. Halve the width and height and you keep only a quarter of the pixels, which usually saves more than any quality setting can.
Fix it in three moves
- Crop first. Cut the picture down to the face or the signature. Every pixel of wall or desk you remove is space you can spend on detail that matters. The image cropper takes seconds.
- Drop the image here. The tool keeps the target at 20 KB. If your form says 15 or 25, change the number and the result updates.
- Check the pixel size your form wants, then download. If the form asks for something like 200 x 230 px, resize to that before compressing, using the image resizer, so the file lands at the right shape and the right weight.
What 20 KB looks like in practice
A passport-style photo
A plain background with your face filling the frame usually ends up a few hundred pixels wide and perfectly clear on screen. A busy background eats the budget quickly and makes the result look smudgy, because every bit of texture has to be stored too.
A signature
Black ink on white paper is the easiest case of all, because there is so little detail to store. A signature can often stay larger in pixels than a photo and still land under 20 KB.
A full photo with a crowd or foliage
This is the hard case. Expect it to shrink a lot in pixels, because fine detail simply costs bytes. If you only need a face from that photo, crop to the face first and the result improves dramatically.
Why the same limit feels harsher for some photos
Two photos with identical pixel sizes can compress very differently. Smooth areas, like a plain wall or a clear sky, are cheap to store. Noisy areas, like grainy night photos, hair, fabric patterns and leaves, are expensive. A photo taken indoors in low light is often grainy, because the camera boosts its sensitivity, and that grain is exactly what a 20 KB budget cannot afford.
So if your result looks worse than you expected, the fix is often not in the tool. Retake the photo near a window in daylight, against a plain wall, and compress that one instead. The difference can be bigger than any setting you could change.
Signature uploads, specifically
Signatures are the most common reason people meet tiny limits. A few habits make them compress beautifully:
- Sign with a dark pen on clean white paper, not on lined paper or a coloured form.
- Photograph or scan it in even light so the paper stays white rather than grey. Grey paper is noise, and noise costs bytes.
- Crop tightly around the signature, leaving only a small margin.
- Keep an unedited copy, so you can try a different crop if the first one is rejected.
Mistakes that make 20 KB harder than it needs to be
- Compressing a screenshot of a photo instead of the original file. A screenshot is a lossy copy of a copy.
- Running the same file through several apps. Each lossy save removes more detail, so start from the original every time.
- Ignoring the file type. If the form wants JPG, keep JPG selected here.
- Sending the photo through a chat app first. Many chat apps recompress pictures when you send them as photos, so send as a document or copy the file over a cable instead.
If 20 KB turns out to be too harsh for what you need, check whether a larger limit is allowed, and try the 50 KB version.
FAQ
Almost every one, but detailed photos have to become much smaller in pixels to fit. Crop first to keep more detail.
The tool aims for the best quality at or just under the limit, which also protects you from forms that count kilobytes slightly differently.
The tool uses 1,024, so 20 KB is 20,480 bytes. A result under that is also under 20,000 bytes in most cases.
Yes. PNG files are saved as JPG or WebP, which are far smaller. Transparent areas turn white, which is usually what a form wants anyway.
No. It is compressed in your browser and never leaves your device.