Compositing Quick Tips - The Photoshop: Professional Retouching and Compositing Tips, Tricks, and Techniques - page 287

Figure 5.7
7. Now we need to add the sky. Go to File > Place Embedded (File > Place in earlier
versions of Photoshop), choose your sky image, and click OK. Use the transform
handles to resize your sky layer so that it fills the layer, and press Return/Enter to
accept the transformation.
Note
You could simply open the file and drag it across, but I prefer to use the Place
Embedded or Place command because it allows me to automatically add the file
into the image I'm working on.
8. With the Move tool selected, use the up and down arrow keys to position the sky
layer so that the horizon line is just slightly beneath it ( Figure 5.8 ) .