Anchor image to page (corner) and dimensions / Aligning images
It would be very nice if you could anchor an image to the page such that the top left corner corresponds to the same corner of the page. If it was also possible to stretch it (optionally keeping image ratio) to 100% of the page, you could easily create sort of a banner.
I understand that MuseScore actually is a piece of notation software. However, as it is possible to include custom images, I think the possibility of aligning them properly can be of use.