As I have some fun on the bulletin boards, toying with photographs, I often see people who have the interest in doing the same type of photo manipulation but do not have the initial know-how to get them started. So this tutorial is dedicated is for them...
First off, you will need 2 images. The first image being the "base" and the second image being the person's head you want to use. The base image I have opted to use is this:
And for argument sake, let's say we want to put Billy Clinton's face on the body of the guy on the right.
So now that we have our two images, we need to start the process of adding Bill to the body-builder image.
I would encourage you to make good use of layers here and do not worry about being exact with every move. By using layers you can always come back and trim up what you have done to make it appear a bit more realistic.
The first step is to select Bill's head. Some prefer to use the magnetic lasso tool as it allows you to outline the head. For me personally, I prefer to select the entire block image and paste it, going back afterwards to trim. Select the entire image by pressing Ctrl + A. Then, move to your base picture, and paste Bill's head as a new layer, Ctrl + V.
Now you have Billy's picture smack in the middle of your base image. Next step is to correctly size the new layer and position it on the new body. From the menu, select Edit > Transform > Scale and size up the image. Hold down the shift key while you resize to maintain the aspect ratio.
Once you are satisfied with the position and scale of your new layer, you will need to trim it up a bit. You might also find that while you are trimming, you will need to adjust the new layer further. In this example, I have also had to do additional scaling and a minor rotate (Edit > Transform > Rotate) to position the head to my liking.
You should now have something similar to this:
Another additional item I would like to point out is the background image. Often times you will be troubled by the existing background image showing through your new layer. I will not go into details on this but I will point out that I typically use the Clone Stamp Tool to replace the unwanted portions of the background that are showing.
Now that you have the image, you could easily stop here. To make this a bit more realistic (and some photos are more difficult than others) you will need to experiment with the Brightness/Contrast (Image > Adjust > Brightness/Contrast) and Color Adjustment (Image > Adjust > Color Balance or Ctrl + B) features of each layer to give you a more balanced final image. Various adjustment layers will help your blending...
In the image above, it is easy to see the differences in the 2 layers. I adjusted the brightness of each layer as well as the colors, however, due to the differences in each photos, the skin tones were a bit more difficult to match.
It is important that you experiment. As with many of these Photoshop tutorials, there is no right or wrong way to accomplish the task at hand so your creativity will play an important factor. =]
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