This is a class allows you to apply a mask to an image much like you could do in PhotoShop, Gimp, or any other such image manipulation programme.
If the mask is smaller than the image then the mask can be placed in various positions (top left, left, top right, left, centre, right, bottom left, bottom, bottom right) or the mask can be resized to the dimensions of the image.
Requires GD 2.0.1+
Because of the nature of the class, masking large images may take some time.
