How to Compress Images Without Losing Quality

Compressing an image means storing the same picture with less data. That can make a page faster, but it does not mean the file is unchanged. Lossy compression rewrites image data. The change can be hard to see, and it is still a real change.

This guide explains what happens when you compress JPG, PNG, and WebP files, then walks through the controls on this site. The tool runs in your browser. It does not upload the image to a server.

What image compression means

An image file holds pixels, color information, and sometimes extra data such as a camera note. Compression looks for a shorter way to store that information.

Two results are possible. The new file can be smaller and look very close to the original. Or the new file can stay large, or even grow, if the format is already efficient or you convert into a format that is a poor match. A smaller number on the quality slider is not a promise of a smaller file.

Lossy and lossless compression

Lossy compression removes detail on purpose. JPG and the WebP setting in this tool are lossy. Fine texture, text edges, and smooth gradients are the first places you may notice it. Saving the same JPG again and again can add more damage, so keep an original if you may need to export again.

Lossless compression keeps the pixel values. A PNG saved at 100% quality in this tool keeps all colors. The file may not get smaller, because a lossless file has less room to discard. A PNG below 100% uses fewer colors. That is not the same control as JPG quality, and it can change flat areas of color.

Some lossy files look identical at a glance. Zoom in, or compare the original and the result with the slider, before you decide the change is acceptable.

How compression affects what you see

Quality and file size are related, but they are not the same measurement. A photo of a sky can shrink a lot at a moderate JPG quality. A screenshot full of text and flat colors can look worse at that same setting and may belong in PNG.

Watch for these signs:

• Soft or blocky areas in the sky, walls, or skin
• Halos around text and logos
• Banding in a smooth gradient
• A transparent area that turned white after a JPG export

If you see those, raise the quality or switch format and compress again. Changing quality, format, resize, or target size replaces the previous result until you compress again.

Compress an image on this site

1. Open the image compressor and add a JPG, PNG, or WebP file. The limit is 20 MB per image.
2. Leave the format on “Keep original format” unless you have a reason to convert.
3. Start with Balanced, which uses 75% encoder quality. Low Compression uses 90%. High Compression uses 50%.
4. Use the quality slider only when you want a custom value from 10% to 100%.
5. Leave resizing off if the pixel dimensions should stay the same.
6. Choose Compress Image. For more than one file, the button compresses each image in turn.
7. Open Compare Image Quality. Use the slider, side-by-side view, and zoom before you download.
8. Download the file. The individual download adds “-compressed” to the name.

If you turn on a target size, the slider no longer picks the encoded quality. The tool searches for a file at or below that size. Turn the target off to use the slider again. A target is a goal, not a guarantee.

Settings that usually hold up

Starting points, not guarantees

JPG cannot store transparency. If the source has a clear area, a JPG export fills it with white. WebP keeps transparency. A transparent PNG keeps every color, so the quality slider does not reduce it.

Common mistakes

• Compressing the only copy. Keep the original until you like the result.
• Judging quality from a tiny thumbnail. Zoom in.
• Converting a simple logo to JPG because someone said JPG is smaller.
• Expecting every PNG to shrink. Many already use compression.
• Treating a target size as exact. The closest valid file can still be larger.
• Assuming a lower quality number always means a smaller download.

Questions

Does “without losing quality” mean the file is identical?

No. A lossless save can keep the pixel values, and even then the container may differ. A lossy save changes data even when the picture looks the same at normal size.

What quality should I use for a photograph?

Start at 75% or 90% for JPG or WebP. Compare it with the original. Move down only if you still need a smaller file and the detail is acceptable.

Why did my PNG get larger?

PNG at 100% keeps colors. If the source was already a small JPG, converting it to PNG often creates a larger file. Stay with JPG or WebP for photos.

Will compressing in the browser upload my image?

No. The image is encoded on this device. Removing it, clearing the list, or leaving the page drops the temporary preview.

Can I undo a compressed download?

The site does not replace your original file. If the download is too soft, compress again from the original at a higher quality.

A practical way to decide

Compress once at a high or balanced setting, compare at a larger zoom, and download only the version you would publish. For a strict size limit, use the guide to reduce an image to 100KB or 200KB. For format choice, read JPG vs PNG vs WebP. If the image is going on a page, continue with image optimization for SEO.