It also has a ludicrously smooth and fast UX and makes it possible to access the high resolution original photographs (up to 100+ megapixels) by modifying url parameters.
Images are served from i.pinimg.com/ and the url params can be changed from "[0-9]+x(\/[0-9a-f]{2}){3}\/[0-9a-f]{32}\.jpg" to "originals/(\/[0-9a-f]{2}){3}\/[0-9a-f]{32}\.(jpg|png)".