Can you compress an image without losing quality? What actually works

Not literally. Making a JPG or WebP smaller always throws away some detail, but at a quality around 80% the loss is usually invisible on screen, and that is the setting to start with in Compress image. If you need truly zero loss, keep the file as PNG and accept a bigger file, or make it smaller in pixels instead of in quality.

Steps

1. Open Compress image and drop your image in.
2. Switch Compress by to Quality. The slider starts at 80%.
3. Under Output format, choose WebP for the web or JPG for anything else. Leave Keep if you must keep the format you have.
4. Drag the divider on the preview across a face, fine text or a sky, where loss shows first.
5. If you see nothing different, try 70%. If you see blocks or smudges, go back up. Then press Download.

What "losing quality" really means

There are two kinds of image formats:

• Lossy (JPG, WebP). The encoder drops detail your eye is unlikely to notice, then stores what is left. A quality setting decides how much it drops. Every save at less than 100% loses a little more.
• Lossless (PNG). Every pixel is stored exactly. Nothing is lost, and the quality setting does nothing, which is why a PNG photo barely shrinks.

So "without losing quality" really means "without losing quality you can see". That depends on the picture and on where it will be shown. A photo on a phone screen hides much more loss than a print or a zoomed-in crop.

Settings that hide the loss

The tool's hint under the slider says the same thing in short: about 80% keeps a photo clean while still shrinking it.

Shrink pixels instead of quality

A 4000 × 3000 photo shown on a 1080 pixel wide phone screen carries far more pixels than anyone sees. Cutting it to 2000 pixels wide in Resize image removes three quarters of the pixels, and good resampling keeps edges sharp at the smaller size. A smaller picture at 90% quality often looks better than a full-size one at 50%, and the file can end up about the same size.

If you have a hard limit, such as 100 KB, switch back to File size mode. The tool then finds the highest quality that fits, so you get the least loss that the limit allows. Our walkthrough of reducing a photo to 100 KB shows how much room that is.

Avoid repeat saves

Each time a JPG is opened and saved again at less than full quality, it loses a little more detail. Compress from the original file, not from a copy you already compressed. If you plan to edit and shrink, do the edits first in the photo editor, which redraws from your original until you save, then compress once.

Questions

Is 100% quality lossless?

Not for JPG or WebP. A 100% JPG keeps the most detail but is still lossy, and the file can be bigger than the original. Use PNG output from Convert image when you need every pixel kept.

Why did my compressed file get bigger?

If the original was already a well-compressed JPG and you chose a high quality, the new file can come out larger. Lower the quality, or use File size mode with a target below the original size.

Does compressing remove photo details like location?

Re-saving drops most hidden metadata, including GPS in most cases. That is not a loss of picture quality, but keep the original if you need it.

Are my images sent anywhere?

No. Compression runs in your browser and the image is not uploaded.