Compress Image

1. 1Add one or more images.
2. 2Drag the quality slider — the estimated output size updates as you move it.
3. 3Compare the original and compressed previews side by side.
4. 4Download the images individually, or all of them as a ZIP.

Each image is decoded, drawn onto a canvas, and re-encoded at the quality you choose. Lossy encoders such as JPEG and WebP discard the detail human vision is least sensitive to — mostly fine colour variation — which is why an image can lose 70% of its file size while looking essentially unchanged.

Quality between 75 and 85 is the practical sweet spot for photographs. Below about 60, JPEG artefacts start appearing around hard edges and in flat areas of colour. Screenshots and graphics with sharp lines behave differently: they compress badly as JPEG and are better left as PNG or converted to WebP.

Optionally the image can be resized at the same time, which usually saves far more than quality alone. A 4000-pixel photo displayed at 1200 pixels wide is carrying more than ten times the data it needs.

Images are decoded by the browser, redrawn on a canvas and re-encoded on your own machine. Nothing is uploaded, so there is no waiting on a queue and no copy of your photos anywhere else.