Awesome !
Could you share a bit about the technique? What kind of glue did you use and did you clear coat etc?
I did some research before hand regarding the issue/myth around sticking stuff on helmets and affecting the helmets integrity etc.
What I have managed to discover is that if you use PVA (wood) glue it will not have any adverse affect on your helmet whether it be fibre glass or polycarbonate.
Regards technique, the first thing you need to do is provide a key for the PVA to stick to. Therefore a good sanding is in order before you start. Then I simply got a copy of the comic I wanted to use and pretty much cut out every little story box so that I had ample to choose from. I then started at the top of the helmet and after applying PVA glue to the cut outs applied them very gently. A bit of patience is needed smoothing out the pictures as they obviously don't sit flat on a round surface. Basically, the smaller the picture, the easier it is to apply. Keep adding pics in any order that pleases you (ok to overlap) until the entire helmet is covered.
I let the pics dry overnight and the next day applied the first of 8 cotas of clear coat. I used the following product, but any acrylic clear coat should do the job.
http://www.plasti-kote.co.uk/Product/pcode---7228/pccode---6751
Now a word of warning. After covering the whole helmet, applying the clear coat and letting it cure overnight, I refitted the visor only to find that because of the extra thickness I had added with the pics and clear coat, my visor was now scraping the area just above my forehead. You will note that area in the picture is now white after I had to remove the pictures and clear coat on that area for the visor to work correctly. In view of this you may wish to check your visor clearances before you start.
Anything else you want to know, just ask....