Multiple variables to change image

[eluser]Unknown[/eluser]
Hello all,

I am trying to make an image swap to another image, based on two variables.

i.e. Change an image of a "blue car with silver wheels" to a "red car with black wheels".

The variables are the 1. colour of the car and 2. colour of the wheels.

Not sure at all about how to do this. Any suggestions?