Grafting comes with its own challenges...as Harry Mudd has pointed out in the forum...you have to sweat body position, skin tone, light position and shading. The first trick, if you're going to do this is to find a couple of great/hi res photos of breasts and keep them. I have a little library of "raw material" the mainstays of which are photos from an early Minka SCORE pictorial and another couple from a SCORE feature on Pandora Peeks....

There are really only so many good "breast" poses...you need a good straight-on shot, and this was what Lara called for.... other shots to gather are another straight-on shot with the model bending over showing lots of cleavage, a three quarters shot, which is what you see the most, and a profile.  You might also be on the lookout for breasts hugged together  and arms-over the head....that more or less covers it.

As in the case of picts of women the larger the image the better....if you're scanning them in..do it at 300 dpi and save it as a jpeg....if you do this you will invariably end up reducing the breasts to fit your image. PhotoShop is great for this and as we all know...reducing images adds to their sharpness, expanding them causes a loss of clarity.

I put guides on my images  so I can use the ellipse select tool to grab the breasts and a little bit of the surrounding area....I always take more than I need and cut it down to fit...itís much easier to pare pixels away than to add them by cloning or copying...

Here's the Pandora file I used for the Lara pict.