I found this link.

Step 1: Get a litrato of your car,something medium resolution is good, if the litrato is two low then the cars parts will look odd, if its a crazy detailed , the final product will look madami fake. The litrato im using is at the bottom of the screen.




Step 2: Go to the cars wolpeyper site-- link and find a car mouth and eyes that suit your picture. It dosent mater if the car is facing left or right, or the perspective angle, we can change all that later. for this one i'm using Flo. Open this wolpeyper at the highest resolution.



Step 3: with your CARS wolpeyper and using the freehand...