1. A computer-implemented method for performing compositing operations on a print data stream comprising at least one image of a first size, wherein the image is associated with a mask of a second size, the method comprising the computer-implemented steps of: comparing the first and second sizes; scaling the image and the mask to a third size, if the first and second size are different; and performing compositing operations using the scaled image and scaled mask, if the first and second sizes are different.