The art styles all have there diffrent things. I think not to sure but one of them switches art because there either not done with that one hard to say and yes i know i did not answer your question. All i can say is pick the one you like best.
There are programs that can extract all the pictures...
BUT....
There is nothing to tie the "random" file names to illustration #'s...
I'm working on it, (slowly!!!), and could post a link when done if someone wants it...
I plan on dividing up the pictures by artist, if I can determine who did what...
Personally... just one art style would have been better.