i took a peek at the graphics and they look rather simple as is, aside the fact that they seem to lack a palette (in a different file i'd assume)
here's what i found out:
judging from the data pattern, this format is tiled.
grey: number of graphics entries (0x2)
red: there's 3 of these per file;
--- first is unknown, i'd believe it's a mode flag,
--- second is the data start address (0x40 for first file)(0x840 for second file)
--- resolution of the file 2x2byte value (0x20 0x20 // 32x32 pixels for both of them)
blue: unknown
yellow: seems to be header filler/garbage data.