scorpion

is it poss to have a pic of a car and change the car color, or put a pic on the bonnet etc.?

phenomenon

ANYTHING is possible in PS...with the proper motivation and time of course...

Changing the colour is fairly easy to do with white body, But you could always select the body (Quick mask, extraction, etc) and desaturate it (shift+ctrl+u) then just paint in the colour you want on a new layer set to overlay, softlight, or colour.

As for putting an image onto the hood/bonnet you can do a quick and dirty one, by just changing the image with the perspective option (Edit>Tranform>Perspective) but if you want it to look realistic then you need to use a displacement map to follow the curves and contours Check this tut for an idea...http://www.thewebmachine.com/ click on Photoshop, then scroll down to the cloth tutorial on the left hand side. Here is a sample of the finished image.
You can use this method to create a displacement map for the car you are working on...in theory...

phenomenon

Here is a VERY quick and dirty idea of what you could do in terms of images onto surfaces. The lighting effect on this needs a lot of work, but you get the idea...

sPECtre

beware! the pixel police is here.

Scorpion, you might need to explore the masking tutorials, to create aselection of the body, and add an hue/sat adjustment layer, that's one of the best ways to change the color of a car (plus the excellent advice given by Phaenomenon!
5btw, welcome to both of you!

scorpion

thanks all