My brother is an illustrator. He owns an A4 scanner, and it seems A2 scanners are too expensive for him.
And he makes most of his creation in A2 format now.
Is there a simple program to scan a grand format with a little scanner and then assemble the whole image?
Photoshop can help. If you ensure that there is an overlap between the various tiles of the scanning procedure you can then use
Photomerge. It will analyze the files you give it and identify common pixels and reposition/overlap the art as it sees fit. With a little care during the scanning process, it can make stitching the tiles together a little less painful.