Show original (uncolored) version of published pieces (maybe a thumbnail that can be rolled over to enlarge).
Some artists are so good at changing/adding/modifying these pieces, it’s hard to tell what they added and what was already there. It can be a pain having to constantly go to the book or page just to see what the uncolored version looks like.
It would be helpful, especially with grayscale, to have a way to flip between your coloring and the original. A toggle switch comes to mind that displays the original artwork so you could see original shadows and highlights or an area you may have covered up. Undo isn’t always possible or practical. Closing out of the custom page to view the original also isn’t always possible and is more time consuming.