Photo editing software?

Here is a quick example of how you can use photoshop to easily change the color of a car.

Start with this image...



Now to change the car color, select the area around the car and copy it to create a layer. Now use the color tool and change the hue of the car in the layer by sliding the hue bar to get the color you want...



Then simply use the eraser tool to erase all the parts of the layer that you don't want...



Then, to finish it off, use the color mask tool on the original base layer to change the blue parts of the interior to black (removing the blue)...



Now that you have that layer created, changing to different colors is as easy as sliding the hue bar anywhere you want it...