Mapping a Texture to a person
1-Open the image that you want to apply a texture to.
2-Make a duplicate of your image by going under the File menu and choosing Duplicate. Then go under the Image menu, under Mode, and choose Grayscale. When the warning dialog appears, click OK to discard the color and convert this duplicate image into a grayscale image.
3-Go under the Filter menu, under Blur and choose Gaussian Blur. Apply a 2-6 pixel blur to your grayscale image and click OK. Now, go under the File menu and choose Save. Name this blurry grayscale image file "Map Grayscale" and save it in Photoshop's native format (PSD file). This is the file you use when applying the Displace filter in step 6.
4-Open the image you want to use as a texture (I scanned a dollar, resized and layered it several times in an 8x10, merged layers and saved to use over for other projects. Yours could be any texture you like-rocks, bricks, canvas, water, tree bark etc).
Press V to switch to the Move tool, press-and-hold the Shift key, and click-and-drag this texture image on top of your original color image. (Pressing-and-holding the Shift key will center the image above the target image of the person).
5-Press Control-A to put a selection around the entire image area. Then to under Filter menu, under Distory and choose Displace. When the Displace dialog appears, enter 10 for both Horizontal Scale and Vertical Scale. Under Displacement Map, choose Stretch To Fit, and for Undefined Areas, Choose Repeat Edge Pixels. Click OK.
6-When you click OK, a dialog appears prompting you to "choose a displacement map". Locate the grayscale file you saved earlier-Step 3, click the Open button, and the Desplace filter will use this map file to texture your image. Youll see your image area warp a bit when you apply this filter. But there is more to do yet.
7-Press Control-D to deselect. In the Layers palette, click on the Eye icon in the far left column beside the texture layer to hide it. Click on your original image layer (I used my son) and use the magic wand tool or selection brush to select the background area behind him.
8-In the Layers palette, click on the texture layer to make it active (your selection should still be in place). Press the Backspace key to leave a silhouette of the texture in the shape of the boy. Deselect by pressing Control-D. At the top left of the Layers palette, change the layer blend mode of this texture layer to Overlay to make it look as if it were tattooed on his skin. You could also use Multiply, Soft Light Layer, Screen for different effects. Lower the layer's Opacity to around 50%. With the texture layer active, use the Eraser tool (E) with a small, hard-edged brush to erase over eyes, lips, teeth and all other areas you don't want the effect.
9-Merge all layers when you are happy with your final touch-ups.