for dbc its F9, the screenshot is taken into the dbc folder next to the exe.
if you use dbp i dont think it has a built in screenshot taker thingy, so you would have to use the 'Prt Scrn' button which makes a copy of the current screen then paste it into some art program. 'Prt Scrn' is embedded into windows, so you could use it for any program, including none db stuff.
or you could make your own screenshot taker. eg.
do
snapshot(57)
loop
function snapshot(key)
if scancode()=key and pause=0 then pause=1
if scancode()=000 and pause=1
pause=0
inc t
save bitmap "snapshot"+str$(t)+".bmp"
endif
endfunction
whats impossible mean?