Crop all the pictures you want from DA or other sites, but don't put it up here.
If someone will, he will get a warning for his first time, and a suspension for the second (if there will be one).
From the rules in that thread. I'm not trying to be a dick here, just trying to be informative. You can't just credit someone and continue to use something that isn't yours. If you want to use it, contact the artist personally and if he doesn't mind then you can use it all you want So, from what I got out of the rules, I suggest either getting permission from OSirois or taking down the signature.