Serve Images in Next-Gen Formats
Replace JPEG and PNG image formats with JPEG 200, JPEG XR and WebP formats. These formats serve with much greater compression and image quality capabilities. These formats will improve page speed and take up less cellular data.
WebP formats oftentimes perform better, but are only supported in Chrome or Opera. If you choose to use this format, you will need to use JPEG or PNG files as a fallback in other browsers.
Browser support for all of these new formats can be found here.
How to convert to WebP
Two of the most widely-used ways to convert to WebP are the cwebp command-line tool or the Imagemin WebP plugin. The former is good for one-time conversions, the latter fora lot of images and major code changes in building code.
Even though there are a multitude of options for compression settings in converting to WebP, the quality setting is generally the option you will use most. Experimenting with the quality range of 0-100 will help you determine a good ratio between quality and file size.