Often, there are very good reasons for switching heads in photos. The photographer or client may like the smile on one pose, and the lighting and body position on another. Rather than reshoot, the photo editor can combine the photos in Photoshop by replacing the head. Of course, this technique also works for creepy or funny effects such as a backward head on a forward body, the wrong heads on the wrong bodies or even the same head on everybody in a group photo.
Select the right photos. Look for similar skin tones and head positions. Scan the photos into your computer, or download them from the Internet. Save them in your "Pictures" folder as JPG's naming them "Photo One" and "Photo Two."
Click "File," then "Open" in Photoshop. Go to "Pictures," select Photo One and click "Open." Again, go to "File," then "Open," select Photo Two and click "Open."
Click the double file icon in the upper right corner of your screen right under the top Toolbar so that both photos appear on the screen. Use the "Move Tool" on the Toolbox at the left of the screen to move the pictures side by side, placing the photo with the head you want to transfer to the left, and the photo with the body you want to keep on the right.
Go to "Layer," then "Duplicate Layer" on the top Toolbar on Photo Two. Click OK.
Place your cursor on the head you want to transfer from Photo One.
Select the "Magnetic Lasso Tool" on the Toolbox on the left. It will be hiding under the regular "Lasso Tool," so click the tiny arrow at the right bottom of the tool square to expose it.
Select the Photo One head by outlining it with the "Magnetic Lasso Tool." Click on the side of the neck and drag the "Lasso" up and around the head shape and across the neckline. Your last click should be on top of the first click, which will connect the "Lasso." Hit "Enter" on your keyboard.
Use the "Move Tool" to drag the Photo One head over to the other photo and place it on top of the Photo Two head. Photoshop will put it on a new layer which you can name "Photo One head."
Check to see if the new head is the right size for Photo Two. If not click "Edit," "Transform" and "Scale." In the frame that pops up around the head, use your cursor to pull a corner of the frame out to enlarge the head, or push it in to shrink it.
Click "Edit" again, "Transform" and "Flip Horizontal" to make the new head face the right direction, if needed.
Click "Edit," "Transform" again and select "Rotate." Drag the curving double arrow in whatever direction tilts the head from Photo One to an angle that looks natural with the body position in Photo Two.
Select the "Smudge Tool" from the Toolbox to blend skin tones where the new neck meets the neck of the old head. If the "Smudge" tool, with the pointer finger icon, is hidden under the "Blur Tool," click the tiny arrow at bottom right on the tool square to find it.
Select the "Eyedropper Tool" from the Toolbox and drag it to the clothing in Photo Two to acquire the colour. Then use the "Brush Tool" to paint in clean edges at the neckline. Make any other adjustments needed,
Click "File," "Save as" and save your altered photo as a PSD to retain the layers. Save it again as a JPG to insert in other documents or attach to e-mails.
The "Magnetic Lasso Tool" automatically adheres to the outline of the shape you're selecting, except where there are many curves and angles. You will need to click more often whenever the shape is irregular. If the outline of the hair on the new head looks harsh and unnatural after you place it in Photo Two, go around the edges with the "Eraser Tool" to soften them, using a soft brush for the eraser. You can also switch heads in group photos using the same techniques.
An obvious change in skin tone or clothing colour, a discrepancy in scale or an unnatural position are dead giveaways that you have altered the photo. People who don't have Photoshop cannot open PSD files, so always make the JPG version available.