Check my WIP image, you see that the overlay can be set over the albumart. It just depends in what order you load something in the widget list, make sure you load the album art first, and the overlay after it, i.e. widget 10 for album art and widget 11 or higher for overlay.
@Harick Widgets are loaded in order, so if you put the Album Art before the overlay in the .ini file it should work. It's how in the default one you get track time on top of the cover. So all you gave to do is change the order the widgets are loaded. Edit: kontirio beat me to it