You may also want to think about how you structure your source art (i.e. photoshop, blender, maya), the exported art to be imported into UE4 (i.e., PNG, JPEG, and FBX), and the game so that art is easy for everyone on your team to re-import.
Mike Erwin did a talk called Blender + Unreal asset pipeline foundations which covers this, and I used this technique in this ArtPipeline sample project.
Some of this goes away if you use tools like Epic’s BlenderTools that import directly from authoring tool to engine.