You know what?
I've uploaded a new Quartz composition to the BeLight Community website!
Yes, a 6th I've named "Layers" as it adds a second layer to Image Tricks 3.
You may:
- adjust opacity of each layer
- select and apply a blend mode
- invert layers order
- select way the second layer content is render (tile, fill, fit or stretch)
Default settings:

Once installed, you'll find this "Layers" Quartz composition in Image Tricks 3 "Utility" category.
Caution: not compatible with 10.4 (sorry for that).
Hope that you'll find this useful.