A browser-based image optimizer which let’s you resize and re-encode images from the browser in many codecs. Made by Google Labs.

It works very well, even on mobile phones, and you can install it since it’s a PWA. As you optimize images, you can zoom and move them around to get a feel for how it will look on different devices. Browser codec support isn’t an issue for previewing images since Squoosh can decode the optimized images so that you can preview them.

The squoosh interface with a test image of an animal, a slider and various settings

You can use it through the command line interface, but I prefer imagemagick instead.