How does the compression actually work?

The image is drawn onto an HTML Canvas element at its original dimensions. The Canvas toBlob() method then re-encodes it as JPEG (for JPG/WebP input) or PNG at the quality value you set. Lower quality means the JPEG encoder discards more high-frequency detail, producing a smaller file.

Why doesn't the quality slider shrink my PNG much?

PNG uses lossless compression, so the Canvas re-encoding doesn't discard pixel data regardless of the quality setting. For significant PNG size reduction, convert to WebP or JPG using the dedicated converter tools.

What quality setting should I use?

75–85% gives a good balance for most web photos. Hero images and product photos: 80–85%. Thumbnails and background images: 60–75%. Below 60% you'll typically see visible JPEG artefacts.

Can I compress multiple images at once?

Currently the tool processes one image at a time. Upload a new file to replace the current one.

Is my image uploaded to a server?

No. The entire process uses the Canvas API in your browser. Your image never leaves your device.

Image Compressor

Compress JPG, PNG, and WebP images client-side using the Canvas API — no uploads, no server.

How to use this tool

1Drop a JPG, PNG, or WebP image onto the upload zone, or click it to browse.
2Drag the Quality slider (1–100) left for a smaller file or right for higher quality — the compressed preview and size stats update automatically.
3Check the Original, Compressed, and Saved stat cards to evaluate the trade-off.
4Click 'Download Compressed' to save the output image to your device.

About Image Compressor

Large image files are one of the most common causes of slow page loads and poor Core Web Vitals scores. This compressor draws your image onto an HTML Canvas element and re-exports it using the browser's toBlob() API at a quality level you control with a slider (1–100). For JPG and WebP, this is lossy re-encoding — lowering the quality value discards fine detail to achieve smaller file sizes. For PNG, the Canvas re-encodes losslessly, so the quality slider has minimal effect; converting a PNG to WebP or JPG is more effective for size reduction. Three stat cards show the original size, compressed size, and percentage saved so you can judge the trade-off before downloading. The compressed image preview updates automatically as you drag the slider. A quality of 75–85 is the sweet spot for most web photos; thumbnails and background images can often go as low as 60 without visible degradation. No file ever leaves your device.

Frequently asked questions

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