1. CSS3 Background-image options

    New properties to affect background images, including background-clip, background-origin and background-size

  2. CSS3 Multiple backgrounds

    Method of using multiple images as a background

  3. CSS3 object-fit/object-position

    Method of specifying how an object (image or video) should fit inside its box. object-fit options include "contain" (fit according to aspect ratio), "fill" (stretches object to fill) and "cover" (overflows box but maintains ratio), where object-position allows the object to be repositioned like background-image does.