Who cleans the mess up?

Manipulation of content seems to be the best description of "Collages". Elements of different origins put together on a surface that wasn't meant for them.
The word collage comes from the french word "coller" to glue and you also need some scissors. Thats how my very first collages were made.
Collages and Art in general is about organizing color, form, composition, rhythm and the interplay of all these in support of the work itself. These are the basics of visual art and as fundamental to digital art work as to the cave paintings of Lascaux.

THE BETTER YOU LOOK THE MORE YOU SEE