Hi,
I'm using tilebackground a lot these days and almost every time I create a "textureWidth" variable and manually set it.
I use it for tiledbg-based healthbar and also some kind of infinite background scrolling.
So the suggestion would be to get this value in expression the same way you have ImageWidth and ImageHeight in the sprite plugin.
This way if I update the texture and it has another dimension, I don't have to keep track of this variable.