Yeah it wasn't. Maybe for a booklet photo like the one in the AEOM cover.
There was said to be a cover with Buffy and Piggie that was made for the Makaveli album, but I think that information originally came from that painter guy. I don't even remember his name, but he wasn't exactly a credible figure. It's not hard to tell that this picture is not a cover format picture, and furthermore, Pac had recorded (and was planning to release) One Nation before he recorded The 7 Day Theory, if I'm not entirely mistaken. So with that in mind it would make no sense to use a cover like this when his next project was gonna be One Nation. He was emotional some times but he wasn't a fucking idiot lol.
I think this hung in the Death Row offices. So I'm thinking the Pac/Biggie and Pac/Dre beefs inspired that painter guy to make this painting, and Pac and Suge liked it so they said "Fuck it, we need to hang this up in the office".