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EVOA Toolbox

Image Compressor

Shrink JPG, PNG, WebP and AVIF images in your browser with a quality slider and a before/after comparison. Files never leave your device.

Processed locally in your browser. Your files are not uploaded.

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What this tool does

Image Compressor re-encodes your pictures with a quality level you choose and shows the new size next to the original. It is meant for the everyday jobs: getting a photo under an email or upload limit, trimming page weight for a website, or sending screenshots without a heavy attachment.

Most of the saving comes from lossy compression. JPEG, WebP and AVIF discard detail the eye is least likely to notice, and the quality slider controls how much. Photos usually tolerate a lot; text, line art and screenshots show artefacts sooner. PNG is lossless, so the slider does not apply to it, and re-saving a PNG in the browser often makes it larger. That is why the tool can keep the original file when the result is not smaller, or convert a PNG photo to WebP or JPEG, where the savings are usually much bigger.

Everything runs locally: the image is decoded with your browser's built-in decoder, drawn on a canvas, and encoded again, using a background worker where the browser allows it. Embedded metadata such as camera data and GPS position is not carried over by this process, and EXIF rotation is applied to the pixels first so photos stay upright. Because your browser's encoder does the work, results differ between browsers and are never guaranteed.

How to use it

  1. 1Drop one or more JPG, PNG, WebP or AVIF images, or choose them from your device.
  2. 2Pick an output format. Keep "Same as input" for the closest result, or try WebP for smaller files.
  3. 3Move the quality slider. Start around 75 and lower it until you can see a difference in the comparison.
  4. 4Optionally limit the maximum width or height to also reduce the pixel count.
  5. 5Press Compress, then check the before/after slider and the size statistics.
  6. 6Download single files, or all results as one ZIP.

Supported formats

Input: JPG/JPEG, PNG, WebP and AVIF (AVIF only where your browser can decode it). Output: the same format, or JPEG, PNG, WebP or AVIF where your browser can encode it.

Privacy

This tool runs in your browser. The data you provide is processed on your device and is not sent to our servers.

Limitations

  • Compression is lossy for JPEG, WebP and AVIF: you cannot recover the original quality from the output. Keep your originals.
  • Sizes are not predictable. Already-optimised images, small icons and noisy photos may shrink little or even grow; the tool reports the real change.
  • WebP and AVIF encoding depends on the browser. If a format is not supported here, it is disabled instead of silently producing another format.
  • Very large images (over about 100 megapixels, or 20,000 px on a side) are refused because browsers cannot reliably allocate that much memory. Animated images are flattened to their first frame.
  • Colour profiles are not carried over, so wide-gamut photos can look slightly different in the output.

FAQ

Which quality setting should I use?

For photos, 70 to 80 is a common starting point and is rarely distinguishable from the original at normal viewing size. Use the comparison slider on your own image: go lower until you spot a difference, then step back up. Screenshots and graphics with sharp text usually need higher values.

Why did my PNG get bigger?

PNG stores every pixel exactly. A browser's PNG encoder is not as aggressive as dedicated optimisers, so re-saving can produce a larger file. Turn on "Keep the original" to get the original back in that case, or switch the output to WebP, which can store the same picture far more compactly (transparency is kept).

Will compression remove metadata?

Yes, in practice: the image is redrawn and encoded fresh, so EXIF, GPS and other embedded data are not copied. If metadata removal is your goal, the Remove Image Metadata tool can do it without re-encoding JPEG or PNG at all.

Are my images uploaded anywhere?

No. Decoding, resizing and encoding all happen in your browser and the files are not sent to a server.

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