> and the output was incorrect (due to missing "board" layer in PCB > output)
As I said, we do have that layer (it's optional, part of the FAB drawing) but yeah, it would probably be better to add that functionality to PCB itself so you have more flexible access to the data you need. It's something I've thought about before, but so far it's been too low priority to actually work on. What you'd really want to do is output GIMP native format, so you can use the GIMP to blend your layers (FR4 is somewhat translucent, as is the solder mask) and output whatever formats you wanted to.
