650 here!
But pictures shouldn't take too much space - almost nothing compared to the actual saves if they're small enough.

<.< 744 mb ....
I think the title bar idea is good too xD
it's always there (except fullscreen) and it wouldn't overwrite a part of the gfx window i mean the picture ... ah you know what i mean XD(at least i hope so)

but i think the title bar is cryptic as it is XD atm there are about 3 values i don't get XD so for any newbie that didn't read this thread would plobably not know what the number in the title bar means XD