When dealing with backgrounds and tiles (and to a lesser extent,
sprites) in GameMaker: Studio it is important to understand
how they are processed internally, as you may discover graphical
artefacts or glitches in your games due to not configuring your
textures correctly for the use you wish to put them to. This is
normally not an issue unless you are scaling the image, but when
designing for devices other than PC or Mac then scaling is almost
inevitable due to the differing screen sizes and the need to adapt
your game to them.
You also have to take into account how the images are stored
internally by GameMaker: Studio on the generated texture
pages, as, if not done correctly, this can also lead to your game
being slow or buggy on devices.
The following sections deal with some of the more complex aspects
of designing backgrounds and tiles for your games, as well as the
use of texture pages: