Are These Sellers Legitimate Authentic Original Posters?

[CinematicFanatic]

I may of posted this in the wrong place, but I am new here so please let me know if this should go in a different sub-forum:

I have looked into places where I can buy posters with the reassurance that they are genuine. I was wondering if anyone could reply with their thoughts on all of the below sites and whether I should be confident buying from them, or not:

https://postermemorabilia.com/

www.eu.movieposter.com

www.starstills.com

www.cinemasterpieces.com

https://www.pastposters.com/

Thanks