I know you can use PNG with transparency, but what I'd love to see in AM is the possibility to create a fe.image object and add an alpha channel to it from a different source image. Like for example
local snapshot = fe,add_artwork ("snap",0,0,200,200)
snapshot.alpha_channel = "faded_borders.png"
so that the transparency of the snapshots is inherited from the "faded_borders.png" greyscale image.
That would open so many neat opportunities for themes.