I prepare make some wallpapers using materials from game ,video. Like the poster,screenshot of game video movie and etc. And I will make a little change on it.then I perpare sell it. Does it any question?
That would be copyright infringement in most counties. The fact that you want to sell them too makes it more actionable in court.
a good rule of thumb is that you can never use a trademarked cartoon, video game, etc character to help advertise your site or turn a profit. Making a non-paid fan site is a different story in many cases.