This style of image mashups is very popular in digital news magazines. Does the style have a specific name?
The technique of pasting images together can be tracked far away since the invention of paper and the term "collage" was used by both Georges Braque and Pablo Picasso it became a distinctive part of modern art (early 20th century).
Colleges, in one way, it's an expression form, a way to achieve an unique meaning from parts with distinct origins, making the total far more meaningful than the original parts sum.
When you use a computer program to make collages, it is correct to use the "digital collage" term.