0 = Opaque: All pixels are drawn in the specified colour. Background objects are not visible.
1 = Transparent: Pixels in the bitmap that have the transparency colour show the colour of the background or of the objects that are underneath this image.
Bit 1:
0 = Normal: No flashing.
1 = Flashing: The flash style and flash rate are determined by the VT design.
Bit 2:
0 = Raw data: Uncompressed data is used.
1 = Run-Length Encoded data (see B.12.2): Run-length encoded data is used. This bit cannot be changed at runtime by a “Change Attribute” command. Changes to this bit are ignored by the VT.