Corresponds to whether the player has already seen the image for the following rooms:

Bit	Room ID	Room Name
00	03	In the Field
01	0E	The Monastery
02	1C	The King's Chamber
03	27	The Oil Room
04	28	The Acid Room
05	3D	The Sea Cavern
06	12	Within the Long Barrow
07	2B	The Hall of the Black Knight

Bit	Room ID	Room Name
00	29	The Treasury
01	13	At the Edge of the Sea
02	N/A	N/A
03	N/A	N/A
04	N/A	N/A
05	N/A	N/A
06	N/A	N/A
07	N/A	N/A

HandlerDisplayRoomImage tests and sets the bit for the current room. The bit number is the room's place in Table_RoomsWithImages.