PDF Medic OnlineCompress image to 20KB
Make a photo smaller than 20KB for a form or an upload — the box below is already set.
Files never leave your device
How to Compress image to 20KB
- Press Choose pictures, or drop one or more on the box above. They are opened in your browser and stay on your device.
- Fit a size is already picked, with 19 in Must be under (KB). If you also see Save as, keep JPG unless your form takes WebP.
- Press Compress. Each picture is fitted under 19 KB on its own.
- Read the notes under the result, look at the picture, then download it.
How a photo gets under 20 KB
The main Compress image page explains the stages Fit a size goes through. At 20 KB the last stage is the one that matters: a full camera photo almost never fits at full size, even at the lowest quality, so the tool also makes it smaller in pixels. The note “To fit, … was also made smaller” then gives the new width and height.
At 20 KB a full camera photo almost always needs that second step. In our test, a detailed 12-megapixel photo of 2.5 MB ended at about 350 × 260 pixels. That is fine for a small thumbnail on a form, but not for a printout.
Crop first, so the 20 KB goes to what matters
A face or a signature usually fills only part of the photo. If you compress the whole photo, most of the 20 KB is spent on the wall, the desk or the paper around it. Cut the picture down first with Crop image, then compress the result here.
For a face photo, Crop image has a Passport 35×45 mm shape. In our test, a portrait cropped to 413 × 531 pixels fitted under 19 KB at its full size, with no pixels taken away. Plain backgrounds and good light help too: smooth areas take far less room than busy or grainy ones.
Signatures and other small pictures
A signature on white paper is mostly empty space, so it is usually small already. If the tool can’t make a picture smaller than the one you gave it, it keeps your original exactly as it was and says so. In our test, a 2.7 KB PNG signature was kept as it was, because any JPG of it came out bigger.
Keep in mind that a picture kept as it was also keeps its type. If your form needs a JPG and your signature is a PNG, change it with Convert image first and check the size after.
Why 19, and why 20 KB is sometimes a minimum
This tool counts 1 KB as 1,024 bytes, so 19 in the box is 19,456 bytes. That stays under 20,000 bytes, which is what 20 KB means on sites that count 1 KB as 1,000 bytes. Typing 20 would allow up to 20,480 bytes.
Some forms give a range rather than a single limit, for example 10 KB to 20 KB. Then the picture must not be too small either. This tool only makes pictures smaller, so if yours is already under the minimum, it cannot help.
Everything happens in your browser: your file is never uploaded to any server. You can check: once your file is open, turn on airplane mode — the tool still works.
Questions
Can a phone photo really fit in 20 KB?
Yes, but only with far fewer pixels. Our 12-megapixel test photo ended at about 350 × 260 pixels. Crop it first so those pixels show the part you need.
Why is my picture smaller in pixels now?
Lowering the quality to 40% was not enough to get under 19 KB, so the tool also reduced the width and height. The note under the result gives the new size.
The form wants an exact size in pixels as well. Can this do it?
Not on this page: it fits the file size, and may change the pixel size to do so. Set the exact width and height first with Resize image, then compress here, and check the note under the result. If it says the picture was made smaller, it had too much detail for 20 KB at that size; a plainer background or better light usually helps.
Can I compress a signature to 20 KB?
Usually yes, and it may already be under 20 KB. Sign on plain white paper, take the photo in good light, cut it tightly around the signature with Crop image, then compress it here.
Is my file uploaded?
No. Compress image to 20KB runs in your browser on your own device. The file is never sent to our server or anyone else. Once your file is open you can even turn on airplane mode.
Is it free?
Yes. No sign-up, no limits on how many files, and no watermark is added to your file.
Does it work on a phone?
Yes, in any modern browser on iPhone, Android, Mac, Windows or Linux. Very large files work best on a computer, because a phone browser has less memory.