Returns the current colour used for drawing to this Image, packed into a number. This is an ARGB integer, where each component takes up one byte, and can be retrieved using bit-shifting and bit-wise and.
Note that the alpha value is stored as a whole number, from 0 to 255.
Yields the current colour used for drawing into the block provided.
Unlike the other version of 'getColors', the 'alpha' value is in it's proper format, a value from 0.0 to 1.0.