After we have applied the UV, we can start to project our textures onto the model. For this, we will use the 'Projection Master' in ZBrush. Using this we can, paint textures, copy areas like the clone stamp in Photoshop, saturate or desaturate our textures and create some deformation, using tools like Deco brush.

Now, what we have to do is choose the tool Plane 3d, and increase your resolution to get more points on the mesh, doing this we get more control points to deform the plane and the texture. Select the alpha for the texture, choose the DragRect stroke, leave the material default and on texture choose your photo. On the Z intensity parameter put 0 to intensity. Now you can apply the photo to the mesh.

You probably wont get a good result on the first projection (like in the ear area), but now you can edit the mesh of the plane, like a simple object in ZBrush, so using move tool, you can adjust the texture on your model.

By doing this whole process again for the other angles, you can get this result.