Hi BlackCelebCollector!
I did a quikc search, it is
this signed poster you're talking about, right?

Here's the scan:
I can tell you that the Chris Evans autograph seems
authentic.

Here's an authentic example:
Jessica's autograph is a nice full signature (which made me doubtful at first) but after further inspection it does seem
authentic, here's another authentic example from AutographWorld.com:
Ioan's autograph on the poster is
authentic too, compare to this in person example from Autograph World:
Lastly, Michael's autograph seems fine to me too, here's another exmaple:
I'd say it's safe to buy (and it's pretty expensive too!). {thumb2} All the signatures seem authentic to me. Usually the "Signature Pieces" auction can be a bit more dicy as it's autographs that were bought that go on sale there, but this one seems fine to me.
Good luck,
zanne