[Enhancement] Ability to define [left center right] for padding with [width=] or [top middle bottom] for [height=]
### Feature request / enhancement
Current functionality seems to be that the other layers in the group are centered based on the size of the background.

Would like the ability to have the background resize to the left, right or center based on width.
And the ability to have the background resize up, down or middle based on height.


