Well, I was going to suggest that you use photoshop to put the pictures in the hexes; however, I found a cooler way.
Since I suck at explaining things, I have pictures for each step.
In illustrator
(1). I assume you have a piece of art you are wanting to use, so go ahead and place that on the screen.
(2). I chose this awesome piece of art.
(3). Go ahead and make your polygon again, then place the polygon over the artwork. Select both the polygon and the picture then right click and select "Make clipping mask."
(4). It should then look something like this.
(5). Do the 3d extrude and bevel again.
(6). Repeat 1-5 and you might even end up with something as sweet as this!
This is pretty helpful, because you don't have to stretch all the art individually to match each hex.
Anyway, I hope that helps.
Just as it is,
Flip Willie