In effect, you can turn any image into a mold and drape a second image over it. Although the basic concepts are the same no matter where you use them, the specifics vary for different programs. Here are some things to keep in mind when using Photoshop's Displace filter. Color mode is important in Photoshop displacement mapping. If the target is a CMYK image, the displacement results are the opposite of what we described above.
Channels control displacement.
Photoshop's Displace filter takes into account the number of channels in the displacement map. Displacing with an RGB map, for example, results in the Red channel's creating the horizontal offset and the Green channel's creating the vertical offset. Photoshop calculates displacement as a percentage. The offset values are expressed as percentages, based on a maximum offset of 128 pixels. For example, a black displacement map with an offset of 50 percent would move a target pixel 64 pixels down and to the right.