Converts an indexed image of type T (eg. ubyte, ushort) into an unindexed type of U (eg. Pixel16Bit, Pixel32Bit).
Converts a 2 Bit indexed image into an unindexed type of U (eg. Pixel16Bit, Pixel32Bit). Word order is: 0: 0b11_00_00_00 1: 0b00_11_00_00 2: 0b00_00_11_00 3: 0b00_00_00_11
Converts a 4 Bit indexed image into an unindexed type of U (eg. Pixel16Bit, Pixel32Bit). Word order is: 0xF0 even, 0x0F odd.