I think there may be a key in FPSC to screen capture - but, really you can just use that 'Print Screen' key and paste your clipboard as a new image in an art package (MSPaint can do that) and save it as JPeg, then post it in the showcase (not here please).
The problem may be that you kinda have to screen cap, quit out, paste and save, then start again to get another screen cap - there are better methods, but they would require a special screen cap software. It's not a good idea to minimise FPSC then go back to it - try and get all your screenies captured while FPSC is running.
If you have Paint Shop Pro, that has a screen capture system built in.
Aegrescit medendo