PDF Medic OnlineCompress image
Make photos smaller in KB — pick a quality, or a size it must fit, like under 50 KB.
Files never leave your device
How to Compress image
- Press Choose pictures, or drop them on the box above. Add more lets you add others.
- Under How small?, pick High quality, Medium or Small file. Or pick Fit a size and type the limit in KB.
- Press Compress and wait for the bar to fill.
- Check the old and new size, then press Download (or Download all (ZIP) for several pictures).
The three levels
Each picture is saved again as a JPG. The three levels only change the JPG quality setting; the width and height in pixels stay the same, so the photo is not made smaller on screen. Medium is selected when you open the page and suits most uses. Choose High quality for photos you may print or crop later, and Small file when the size matters more than fine detail.
How much smaller the file gets depends on the photo. A large photo straight from a phone camera usually shrinks a lot. A picture that was already saved as a small JPG may hardly change.
- High quality: JPG quality 85 out of 100.
- Medium (selected at the start): quality 70.
- Small file: quality 50. Zoom in on faces and small text before you send it.
Fit a size: for forms with a KB limit
Choose Fit a size and type the limit in the box Must be under (KB). The tool then looks for the best result under that number, in three stages:
If the picture still cannot get under the limit, for example a limit of a few KB, you get the smallest version it reached, with a message saying so. The box takes KB, where 1 KB is 1,024 bytes. Some websites count 1 KB as 1,000 bytes, so type a little less than the limit to be safe: 19 for 20 KB, 48 for 50 KB, 95 for 100 KB, 190 for 200 KB. The number can be typed in Arabic digits too.
- First it keeps every pixel and searches for the highest JPG quality that fits, between 92 and 40.
- If even quality 40 is too big, it makes the picture smaller in pixels, step by step, at quality 75, until it fits. You are told the new width and height.
- Once it fits, it uses the room left under your limit to raise the quality again, up to 92.
PNG, WebP and iPhone photos
PNG pictures are saved as JPG here, because JPG is much smaller for photos. JPG has no see-through areas, so a transparent background turns white. If your browser can save WebP pictures, a Save as choice appears with JPG and WebP. WebP keeps see-through areas and is often smaller, but some forms and older programs do not accept it. If you don’t see the choice, everything is saved as JPG.
iPhone photos in HEIC format open only in browsers that can read HEIC, such as Safari on iPhone, iPad and Mac. Other browsers show a message instead. HEIC is already a very compact format, so its JPG version can come out larger; in that case the HEIC photo is kept as it is (see below). If a form needs a JPG, use Convert image first, then compress the JPG.
Never a bigger file, and no hidden photo details
If the compressed version would be the same size or bigger than your picture, you get your original back unchanged, with its name and format, and the message says it was kept as it was. This happens with pictures that were already well compressed.
Every new file is drawn from scratch in your browser, so the details a camera hides inside a photo are left out: the camera model, the date and time, and often the GPS location where it was taken. That is worth knowing before you post a photo of your home or children. A picture returned unchanged keeps those details. The photo is also saved upright, so it no longer shows sideways in programs that ignore the rotation note a phone adds.
Browsers can only draw about 16 megapixels at once, so a larger picture is scaled down to that size first. Your original file is never changed; you download a new one.
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
How do I compress an image to 50 KB?
Choose the picture, pick Fit a size and type 48 (a little under 50, to be safe). Press Compress. For 20 KB type 19, for 100 KB type 95. If the photo is too big to fit at full size, it is also made smaller in pixels, and you are told the new size.
Can I reduce photo size without losing quality?
Not completely: saving as JPG always drops some fine detail. High quality keeps the loss small and is hard to see on a screen. Fit a size aims for the best quality that still fits your limit.
Why did I get my picture back unchanged?
The compressed version would have been the same size or bigger, so the tool kept your original instead. The picture was already well compressed. Try Small file, or Fit a size with a lower number.
Why did my PNG’s transparent background turn white?
The picture was saved as JPG, which cannot be see-through. If the Save as choice shows WebP, pick it to keep the transparency. To keep a PNG as PNG, use Resize image instead: fewer pixels usually give a smaller PNG.
Can I compress several photos at once?
Yes. Choose them together or use Add more. Each one gets the same setting, and Download all (ZIP) saves them in one go. With Fit a size, the limit applies to each picture on its own, not to all of them together.
Can it make an image bigger in KB, to reach a minimum size?
No. This tool only makes pictures smaller, and it never returns a file bigger than the one you chose.
Is my file uploaded?
No. Compress image 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.