There suppose to be more of painting files. Like Model or something, cuz i havent seen any String on taking texture.
EntityPainting uses an ENUM to describe paintings. The texture path is handled by the renderer, but the ENUM describes the painting name ("skull") as well as its UV position in the texture and width and height (UVWH are all full-block values, eg. 0,0 with width/height 1,1 would be a 1x1 painting located in the upper left of the texture, which at the default resolution would be 16x16 pixels).