If the Global Color Table Flag is set to 1, the value in this field is used to calculate the number of bytes contained in the Global Color Table. To determine that actual size of the color table, raise 2 to [the value of the field + 1]. Even if there is no Global Color Table specified, set this field according to the above formula so that decoders can choose the best graphics mode to display the stream in.
Assembly: GifComponents (Module: GifComponents) Version: 0.1.3594.26453
This is the value of the globalColourTableSizeBits parameter passed to the constructor.