So...this is probably the most amazing Metrocard art website out there.
Upload an image to receive the picture translated into a Metrocard Mosaic.
Here's an example, with Mayor Bloomberg.
This website wass created by amazing artist Nina Boesch, who currently ranks as my favorite metrocard artist, ever.
I heartily recommend her websites, you can purchase copies of your Metrocard Mosaic images as well. Truly an incredible idea.