I kind of understand why Blitz does this, but the way animated textures are handled is kind of a pain. You have to keep the handle of the brush applied to the surface, call BrushTexture whenever you want to change the frame of the texture, and call PaintSurface to actually see the changed frame. While this gives you a lot of control over the animated texture, I would love a default animated texture where you can define an optional framerate in LoadAnimTexture and the texture will simply loop at that framerate.