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

Bit	Room ID	Room Name
00	02	A Wooded Vale
01	07	The Evaporation Pits
02	10	The Shrine Of The Nemed
03	17	The Burial Pit
04	49	The Main Courtyard
05	38	The Deserted Broch
06	43	The Crystal Cavern
07	40	The Circle of Stones

Bit	Room ID	Room Name
00	4F	The Fomorians' Cavern
01	2A	The Lake
02	52	The Danaan Settlement
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

Used by the routine at Handler_DisplayRoomImage but uses the bit index from Table_RoomsWithImages.