Implement a way to show all textures, reliefs or other .bmp and .png used in an assembly of part. For example it could be integrated like the 3rd party files in the model tree.
Working with Vault, textures and reliefs, but also sticker, can be quiet a problem. Especially when you move old parts from an older multiuser project into vault, upgrades made problems too.
Sometimes the parts still refer to the old texture path and that makes it impossible to check them in. In any big assembly you have to check every single part for its used (and unused but included) textures, by looking in every single colour definition.