Image Resizer & Compressor

Resizing changes the pixel dimensions — a 4000 pixel wide photo becomes 1200 pixels wide, and the discarded pixels are gone. Compressing keeps the dimensions and reduces how precisely each pixel is stored. Resizing usually saves far more space, because file size scales with area: halving both dimensions removes about three quarters of the data.

Match the display size, then double it for high-density screens. A full-width hero at 1200 CSS pixels wants a 2400 pixel source; a thumbnail shown at 300 pixels wants 600. Serving a 4000 pixel photo into a 300 pixel slot wastes bandwidth on every single page load and is one of the most common causes of a slow site.

Scaling down is safe — the browser averages pixels together and the result stays sharp. Scaling up cannot invent detail that was never captured, so an enlarged image will always look softer than the original. If you need a larger image, go back to the original file rather than enlarging a small copy.

By default yes — enter a width and the height follows automatically. Unlock the ratio if you deliberately need to stretch to fixed dimensions, but be aware that any non-proportional change will visibly distort faces and straight lines.