I have two images I would like to composite because I found that my image looks better with one section not antialiased. I have 3 images. The first completely antialiased, the second with no antialiasing, and the third a mask of the section (sofa pillows) I'd like to not have antialiasing in the final image. In easy, step-by-step language, how can I composite these images so only the pillows are not antialiased? Note: These images were created in another app.