How to Compress an Image Without Losing Quality

Images are usually the heaviest part of a web page and the most common reason an upload form rejects a file. Compressing them well can cut file size by half or more while the picture looks the same to the eye. This guide explains how image compression works, which settings to use, and how to hit an exact file size when a form demands one.

Lossy vs lossless compression

• Lossy compression (JPG and lossy WebP) throws away detail the eye is unlikely to notice, such as subtle colour variation in busy areas. It gives the biggest savings and suits photographs.
• Lossless compression (PNG and lossless WebP) keeps every pixel exactly and only stores the data more efficiently. It suits logos, screenshots, diagrams and anything with sharp edges or text.

Because of this, the most effective way to shrink a photo is almost always a lossy format at a sensible quality setting, while graphics should stay lossless so edges don't pick up blotchy artefacts.

Compress an image step by step

Open the Image Compressor and drop in one image or a whole batch of JPG, PNG or WebP files. Everything runs in your browser, so your photos are never uploaded.

• Choose Quality mode and set the slider. For photos, 70-80% is the usual sweet spot where files shrink a lot with no visible change.
• Or choose Target Size mode and enter the size you need, such as 100 KB or 200 KB. The tool searches for the highest quality that fits.
• Pick the output format: keep the original, or switch to WebP for smaller files at the same visual quality.
• Optionally set a maximum width to scale down oversized photos, which often saves more than quality settings alone.
• Compare before and after, then download individual files or the whole batch.

Resolution matters more than quality

A modern phone photo is often 4000 × 3000 pixels, but a blog column or product card rarely displays images wider than 800-1600 pixels. Halving the width and height leaves a quarter of the pixels, which cuts file size far more than lowering quality ever could. For the web, a good rule is to size images to about twice their largest display width, which keeps them sharp on high-density screens without wasting bytes.

If you only need to change dimensions, use the Image Resizer, which can also resize to an exact file size in KB.

Recommended settings by use

• Website photos: WebP at 75-80% quality, no wider than about 1600 px.
• Email attachments: JPG at 70-80%, around 1200-2000 px wide.
• Online forms with a size limit: Target Size mode, set a little under the limit to be safe.
• Logos, icons and screenshots: PNG or lossless WebP, and resize rather than lowering quality.
• Printing: keep the original, since print needs far more pixels than screens.

Common mistakes

Compressing the same JPG again and again adds new artefacts each time, so always start from the original file. Saving a screenshot or logo as JPG creates fuzzy halos around text and edges; keep those as PNG. And converting a JPG photo to PNG makes it bigger, not smaller, because PNG stores every pixel losslessly.

Need a different format rather than a smaller file? The Image Converter switches between JPG, PNG, WebP, GIF, BMP and ICO.

How much can I compress without losing quality?

For typical photos, 70-80% quality usually saves 50-70% of the file size with no difference you can see at normal viewing size. Converting to WebP often saves another 25-35% on top. Busy, detailed photos compress less than smooth ones like skies or studio shots, so check a zoomed-in preview for important images before publishing.