Promoting paysite with puchased content upsets sponsor?

[DirtyDani]

Hey everyone,

I've been building/submitting galleries for a few months now and have had some success promoting some of the larger sponsors with purchased content, so I thought I'd try out a couple of the smaller programs to see what kind of difference it would make. So I bought some pretty nice niche content to promote a smaller paysite in the same niche and I got an email (it sounded kind of angry, but I don't know) this morning from the paysite owner asking me what the heck I was doing promoting his site using content that was not his... Is this a common faux pas in the industry? I thought most sponsors encouraged using fresh, semi-exclusive content to promote their sites rather than the stuff any affiliate can use for free... I'm a little confused, should I be contacting sponsors and asking if I can use purchased content?
It's not that they're bad pics, either, I thought it was a good gallery...

Please enlighten me!

Thanks!!

Danielle