How do I compress an image without losing quality?
To compress an image, open FixDoks's Compress Image tool, add your JPG, PNG, WebP or HEIC photo, and pick a quality level or a target size in KB. The tool re-encodes JPGs and WebPs and reduces PNG colours to shrink the file while keeping it sharp. Everything runs in your browser, so photos are never uploaded.
Compress Image at a glance
| Input | JPG, PNG, WebP, HEIC |
|---|---|
| Output | Compressed JPG, PNG or WebP |
| Processing | In your browser; your files are not uploaded |
| Price | Free, no watermark |
| Download | Free Google sign-in |
| Works on | Chrome, Edge, Safari and Firefox on Windows, Mac, Android and iPhone |
How to use Compress Image
- Click Select images or drop your JPG, PNG, WebP or HEIC files onto the box. You can add many at once.
- Choose By quality to set a quality level, or By target size to hit an exact size in KB.
- Click Compress images, then download each file or all of them as a ZIP.
How does image compression work?
Photos straight from a phone camera are often 3 to 8 MB. Most of that data is detail your eye cannot see on a screen. FixDoks re-encodes the image with a smarter quality setting, which removes invisible detail and keeps what matters, so a large phone photo usually shrinks to a fraction of its size and still looks the same.
JPG, PNG and WebP are compressed differently
JPG is best for photos. The quality slider controls how much fine detail is kept. PNG is lossless, so a quality slider alone does nothing. For PNG files FixDoks uses real colour quantisation: it builds an optimised palette of up to 256 colours and maps every pixel to it, the same technique used by dedicated PNG optimisers. Screenshots, logos and graphics often shrink by 50 to 80% this way while keeping transparency. WebP is a modern format that is usually smaller than JPG at the same quality and works in every current browser.
Which quality should I pick?
For sharing on WhatsApp, email or the web, 60 to 75% is the sweet spot. Go to 80 to 90% if you plan to print. Below 40% you will start to see blocky artefacts around edges. For PNG, lower quality means fewer colours: photos with smooth gradients need more colours than flat graphics.
Hit an exact size
Choose By target size when a form or website says something like "maximum 200 KB". The tool searches for the best quality that fits under the limit and scales the image down only if it has to. There are also one-click pages for common limits: 20 KB, 50 KB, 100 KB, 200 KB, 500 KB and 1 MB.
Never bigger than the original
If a file is already well optimised and re-compressing would make it larger, the tool keeps your original instead. You always get the smaller of the two.
Batch compression and file names
Add a whole set of photos at once, for example the pictures from a trip or a product shoot. They are processed one after another so the page stays responsive even with large files, and each row shows the size before and after with the percentage saved. Every compressed file keeps its original name, so you can drop them back into the same folder. If you change the output format, only the extension changes, for example holiday.heic becomes holiday.jpg.
Common questions about results
- A file got only slightly smaller. It was probably already compressed, for example a photo downloaded from social media. There is little left to remove without visible damage.
- A PNG stayed large. PNG photos compress poorly. Convert them to JPG or WebP for a much smaller file.
- Colours look a little different. Browsers convert images to the standard sRGB colour space. Photos from professional cameras set to Adobe RGB may look slightly less saturated.