Allow multiple PNG in feedback to utilise transparency.

[CrispedToast]

I currently have buttons that have a PNG background and feebacks that 'illuminate' various combinatons of small LEDs at the bottom of the button. This is achieved by using feedback to change to PNG to 'button graphic WITH one LED', or 'button graphic with two LED', or 'button graphic with three LED' etc
I wonder if it would be a useful option (it certainly would to me!) to overlay a PNG and take advantage of its transparency to allow the original PNG (or even other feedbacks) to exist along with the transparent PNG. Thus you could have a feedback to 'illuminate' LED#1 and a separate feedback to 'illuminate' LED#2 without the current workaround of having to use a lot of logic statements in the feedback to load the appropriate PNG.