(take-screenshot #&optional (template (string-append (user-home) "/screenshot%y%m%d%H%M%S.xwd")))
Take a snapshot of the whole screen. The screenshot will be saved in xwd format in the filename constructed from TEMPLATE. %-escapes in TEMPLATE will be replaced by time-elements, according to strftime rules. TEMPLATE defaults to the file "screenshot%y%m%d%H%M%S.xwd" in the user's home directory.