As it is now, any sketch (including the expensive masterpiece sketches) is completely stuck on the item or structure it's applied to. If the item or structure is destroyed, replaced or rendered useless (for example, by moving elsewhere and leaving non-liftable structures behind) the sketch is completely lost. (For example, if I were to move my barter stands to Sevilla, I would have to use new sketches to pimp my barter stands, and the existing ones would be wasted.) This makes me a bit hesitant to apply Masterpiece Sketches, considering they're not cheap for mere in-game images.
It would be nice if we could somehow transfer sketches between items and structures, for example by destroying the item/structure it's currently on.