BYTE[1] 0x90
BYTE[4] Map Serial
BYTE[2] Gump Art (usually is 0x139D) For Corner Image
BYTE[2] Upper Left X
BYTE[2] Upper Left Y
BYTE[2] Lower Right X
BYTE[2] Lower Right Y
BYTE[2] Gump Width
BYTE[2] Gump Height
BYTE[2] Facet ID (same as in facetXX.mul files)