Image Resizer

Because enlarging cannot recover detail that was never in the file. The extra pixels are interpolated from neighbours, so you get a softer image in a larger file. If you need the bigger canvas anyway, tick allow upscaling and it will proceed.

This is that — resize image online, in the page, with nothing uploaded and nothing to install. Resize JPG, PNG, WebP or HEIC the same way, since the decoding happens in your browser rather than at a server that would have to be sent the picture first.

That is most of what it is used for. A photo off a modern phone is four thousand pixels wide and several megabytes, which is wasted on a website, an email or a form that will refuse it — this resizes it on your device, HEIC included, and shows you the result before anything is downloaded.

Yes. Drop one in and it resizes like any other image, coming back as JPEG, PNG or WebP — which is usually what you wanted anyway, since a resized photo is normally on its way somewhere that will not accept HEIC.

Leave the aspect ratio locked, which is the default, and set only one dimension. The other is calculated to match. Unlock it only when you deliberately want to stretch or squash the picture to fit a fixed box.

No. The image is read from disk into your browser and resized using the browser's own graphics pipeline. Nothing is transmitted, so it is safe for photos of people, documents or anything containing location data.

Usually, yes, and often dramatically, since file size scales roughly with pixel count. If you want to reduce size without changing dimensions, use the compressor instead, which re-encodes at a lower quality.

JPEG, PNG, WebP and HEIC. The output keeps the input format by default, so a PNG stays a PNG with its transparency intact. Use the converter if you also want to change format.