PicPerf's Image Saver

This extension allows you to convert any image on the web from one format to another. For example, if you'd like to save an animated WebP as a GIF for better compatibility, just right-click and download it to your machine. It supports all modern image formats for the web, including JPEG XL. Keep in mind that the quality of the conversion will depend on a format's capabilities (if you transform a PNG to JPEG, don't expect transparency to stick around).