How can I return images depending on users selection?

I have a need to return images based on user selection, the complication I have is the image needs to change three times based on three different users inputs. If I use a car dealership as an example: Firstly I want the user to select a Make of car from a dropdown which returns a generic image of the brand selected, then the user selects the Model of car (separate dropdown) which changes the image to a generic image of that model and finally the user will select the derivative (third dropdown) which shows a specific images of the car selected.
I am using wpmu directory plugin and have tried to get the desired results (unsuccessfully) with Gravity Forms conditional logic.
The potential results are approx. 6,000 images; the first dropdown will have approx. 20 options, each of these will have approx. 30 choices and the final approx. 10.
Any suggestions in producing this would be greatly appreciated.

Dan