How simulate paper car folding from image?

I believe you need to slice the image for each surface. In short, what you are doing right now is importing an image as a flat file, and creating a parametric model on a layer above that.

Or you could project the image onto all 4/5/6 planes needed, and crop each view accordingly (?) Just a guess.

I agree with Mashi here.
You will need to split the image up into separate images that will be applied to each face. It doesn't matter that they will be rectangular.

You will then need to create separate face styles inside the sheet metal part. Each face style will have one of the images as a texture. The use Part Painter to paint the appropriate face styles onto the appropriate faces. You may need to go back to individual styles to adjust their rotation angle.

HTH