Alert Reader Yahooguntu asked the following:
Can you write a tutorial on how to take the head off someone in one picture and put it in place of someone else's head in another picture?And of course the answer is "yes, I can". However, I will write it in blocks so that the various techniques needed to do this project can be understood discretely and people can learn at their own pace.
So what we're going to do is take this picture of the pro wrestler Batista:
And this picture of my friend Phil:
And we're going to create this irresistible hunk of man-flesh:
Now, for those who are self-starters, here are the steps we are going to follow, and if you can invent steps for yourself between posts here at GiMP University, go ahead and work at your own pace. The rest of you will have to wait for my amateur pace posts.
 Create a working image for our project
 Remove the head from the victim
 Place the head in the target image -- including scaling, color correcting, and cleaning up
 cleaning up target image for final use
And to keep you from completely giving up on me, we'll do step 1 now as it is relatively easy. If you click on the image of the young body builder, it will open up in its own window, and from there you can download it to your desktop (same with the picture of Phil, fwiw).
Now, to keep us all on the same page, open that image in GiMP and do the following simple adjustments:
[a] duplicate the image using the "Image" menu, clicking "Image > Duplicate". Close the original in case you make a fatal error and have to start over.
[b] Double the size of your target image to 782 pixels wide, and allow GiMP to scale the height using the "Image > Scale Image ..." menu
[d] Use the Layers window and add a new layer to the target image. You can name it "new head" if you need that much help.
Just to answer your question before you ask it, we are blowing up this image to double the resolution to do our editing work so that when we have finished all the cutting and pasting, tiny flaws will get minimized when we blow the image back down to it's original size -- or smaller. That's a key tip which you should have seen elsewhere on this site: you want to do your editing work at double resolution so that you can worry about big stuff and not get consumed with pixel-level perfection.
More next time.