For what it's worth, I crop my thumbnails because I would rather show a portion of the picture at higher detail than I can display by resizing the whole image. You may not be able to get the "whole picture" but I hope that way people get a feel for my style so that they can decide whether or not to view the pic in its entirety.

...@thefixer:
I agree entirely! I don't click on the generic "Content Advisory" thumbs either. There's absolutely no way to tell what you're getting into. I do like to view the occasional nude, but I have no desire to click through a hundred pics of expressionless drivel to find one or two remarkable pieces...... 
at least before, I could make that decision based on the thumbnail.... :sad:

<-insert words of wisdom here->