Assuming your resolution is high enough, this screenshots a level, at it's center, when alt + 1 is pressed.
PHP Code:
//#CLIENTSIDE
function GraalControl.onKeyDown(temp.keycode, temp.keystring, temp.scancode) {
if (keycode == 1073)
makescreenshot2("screenshot" @ int(random(100000,999999)) @ ".png", 0x3f, player.level.width / 2, player.level.height / 2, player.z, player.level.width * 16, player.level.height * 16);
}