Questions relating to Dianoga - an image optimisation extension for Sitecore. It is used to reduce the weight of pages served by automatically using appropriate compression on JPG, PNG and SVG images served from Sitecore's media library.
While Sitecore includes some basic image resizing behaviour out of the box, Dianoga improves on this by offering better image compression techniques on top of the default behaviour.
By default it supports the three of the most common image formats for Sitecore websites (JPG, PNG and SVG) however it is also extensible so projects with specific needs for image optimisation can add new processors specific to their needs.
Source and documentation are available via https://github.com/kamsar/Dianoga
This tag can be applied to questions relating to installing and using this tool.