What is the best way to quickly create custom printed parts for ldraw?

[tom alphin]

I had a selection of 2x2 and 2x4 printed tiles made, and want to use them in my building instructions.  The images are in both PNG (bitmap) and AI (vector) formats.  

What is the easiest way to make these into custom printed parts for use in MLCad /LDraw, etc?  I would like to believe that there is an app that makes this trivial.

thanks,
---tom