Backgrounds artist
From what I have researched about background artist that it is used to describe a person who uses traditional or digital artistic skills to design the backgrounds for animations, films, video games or other visual story telling platforms. Animation background artist jobs are often divided into two types: 2D artists and 3D artists.
Compositing
A compositor is someone who helps create the final image of a frame, shot or sequence. They take different elements and put them together to make a believable picture.
Animator
Animators use sequential images of drawings, puppets and models to produce films.