Cardboard images?
I'm not quite sure what you mean by that, but it matters little because this is a really awesome picture. It's always great when artists show tributes to their heroes. It's great how every single thing here has a different color and shading. It's great to see how it all weaves together to form a great picture. Again, you are really good with hair even though this was not shown with little hairs. I love how the background is made up of these strange red fibers or something.
Collages are always something I have looked for in terms of art. While I haven't seen that many photos of the guy, this is done very well to make a realistic portrait. Were you trying to show trouble in his eyes? I guess I've reviewed too many art pieces I keep looking for hidden meaning. I'm surprised this doesn't have more views.