Until someone comes up with a better response, you might be
stuck with what the rest of us call trial-and-error. There's (I
hope) limited documentation which is a start - print that out and
get ready to start appending your own notes.
I use to use CFX_Image (or was it CFX_img?), but too often
the thumbnail looked crappy and my client were not pleased. I've
since changed the shopping carts so that the client can upload 2-3
graphics for each product and if anything comes out crappy its
within their power to change it.
Your ambitions it seems are notable, don't forget to turn a
profit.
T