I remember of a PD rom that behaved as a GB Printer, you would link up 2 gameboys, the gameboy would with the gbprinter rom would display on screen what the other gameboy "printed".
I don't remember if this rom saved the printed pictures. But maybe you can look into that?
EDIT: and by that i mean if you can link up 2 gameboys, one with the gbcamera, the other with the "gbprinter rom" (flashed on your EMS) you can then backup the save file from the gbprinter rom and use it.
EDIT2: the name of the rom is Gameboy Printer Emulator V1.0 by Jeff Frohwein (PD). I'd post a link to it, but I'm not sure it'd be legal since the site also hosts illegal roms.