This tutorial will show you how to make a line stretch, but with a person instead of a background, it looks really cool.
For this tutorial you should use a psd, because of the transparent background.
Open up a new image with a white background or whatever color.
Copy and paste the psd onto the white background like this:
Use the Move Tool and move it to the far right or left, depends on what your doing.
Go to your Tools Palette and and click on the Single Column Marquee you can find this where the Rectangular Marquee Tool is next to the Move Tool .
Now depending on what direction you want the line stretch to go, click either on the very TOP, LEFT, RIGHT or BOTTOM. You should see a dashed line moving like this:
Press CTRL+T and you will see 3 boxes appear in the place the moving dashed line is at.
Now click on the middle box with your mouse and drag to the opposite side of the image.
Drag all the way to the opposite end.
Next right click on the Single Colum Marquee, a pop up will come up asking to Apply Transformation, click OK.
Click CTRL+ D to Deselect the image.
Add a New Layer, (Layer >> Add >> Layer)
Copy and paste the psd again on the New Layer
Using your Move Tool, move the image of the psd you just copied over on top of the other, like this: