In the current line-of-sight system of Byond, the turfs not in sight are completely hidden. Even if you wanted to put image() there, it wouldn't show up until the turf can be seen. There should be some kind of override, if you always wanted the image to be seen, no matter if you're blind or not in LOS.
That feature is essential in my next game. Can it be done?
/Andreas
I'll put in on The List. As I mentioned to Deadron, we need slightly better control over images and layers, and your sugestion fits in there. We'll come up with something, but I can't promise you anything immediate, as we have bugs to fix.