For decades, the computer graphics world has strived to find a way to have graphic resources (images) in a proper format so that they can scale on different resolutions or screen densities without impacting the resource space/memory side too much.
Today, since this scenario is evolving faster and quickly adding diversity (and thus, complexity), we cannot rely on the old-fashioned idea of a single bitmap that fits all situations. Today's graphic resources need to be provided in different versions so that they're used according to the real capabilities of the target device running the application. This is the reason the FMX.MultiResBitmap unit exists.
The basic idea is to provide a collection of different versions of the image, each suited to a different scale (or pixel density, as you may prefer to call it), as opposed to there being a single version. Having an automatic mechanism to deal with dynamically selecting the best option...
