R.E. Load pretty much has a step by step instruction page on their site to order their bags.

http://reloadbags.com/bags/build.php

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re-read second part

Line drawings. Illustrations with solid colors, not fading or shading. R.E. Load is really good at this appleque stuff, just send them a picture that you like and they will tell you if it works out. The artwork they did on a bag I ordered was awesome.

-ray