What is an acceptable pic for adding a new babe?

First a disclaimer: this is an honest question and I'm not trying to be a polemic smartass. The idea is being able to help in getting some girls that I like added...
I have in mind principally questions related to copyright, authorizations and the likes.
Look for instance at this thread (Caroline Fox).
Frigo asked for a pic in order to being able to add her and simply putting up on an image hosting site some pics from apparently a Karupspc proprietary set did the trick.
Look instead at this thread (Martina aka Margarita Eromaxx).
Apparently the only obstacle to adding her was the lack of a suitable pic (look at the other thread...), Stemcell attached a couple of beautiful photos from her freely accessible model page on Eromaxx (providing also the links) and yet apparently this was not kosher...
So the case is that some sites (karupspc in this occurrence) are a positive exception, and anything from them -even a photo from a proprietary set- is ok?
Or maybe (the same thing with a different slant) there are sites that are negative exceptions (eromaxx in this case) and anything from them -even freely accessible/promo/etc. etc.- is not ok?
Or even more simple, the divide is beetween the clickable sites and the other?
(Since it is reasonable -at least to me- that in the first case probably there would be no problems at all in using one of their pics, since there is already some sort of 'business relationship', while in the other maybe it is the case that better safe than sorry...).
In other words:
if I will do an add post for Martina with pics taken from Beauty and the Senior and/or Old Farts & Young Tarts, it will works this time?

I have in mind principally questions related to copyright, authorizations and the likes.
Look for instance at this thread (Caroline Fox).
Frigo asked for a pic in order to being able to add her and simply putting up on an image hosting site some pics from apparently a Karupspc proprietary set did the trick.
Look instead at this thread (Martina aka Margarita Eromaxx).
Apparently the only obstacle to adding her was the lack of a suitable pic (look at the other thread...), Stemcell attached a couple of beautiful photos from her freely accessible model page on Eromaxx (providing also the links) and yet apparently this was not kosher...
So the case is that some sites (karupspc in this occurrence) are a positive exception, and anything from them -even a photo from a proprietary set- is ok?
Or maybe (the same thing with a different slant) there are sites that are negative exceptions (eromaxx in this case) and anything from them -even freely accessible/promo/etc. etc.- is not ok?
Or even more simple, the divide is beetween the clickable sites and the other?
(Since it is reasonable -at least to me- that in the first case probably there would be no problems at all in using one of their pics, since there is already some sort of 'business relationship', while in the other maybe it is the case that better safe than sorry...).
In other words:
if I will do an add post for Martina with pics taken from Beauty and the Senior and/or Old Farts & Young Tarts, it will works this time?


