The wiki's unofficial official policy on this (which came out of a discussion among wiki admins awhile back) is that the wiki:
- Prefers un-credited (ie.name-less) screenshots: they're more encyclopedia-like, and the wiki is P99's encyclopedia
- If there is no picture of a something already, it is acceptable to upload one that is "credited": the wiki is better off having credited pictures than none at all
- Because of the above two, you are allowed to replace a credited picture with an uncredited one
- However, what you are not allowed to do is take an existing picture (credited or not) and replace it with another screenshot just to get your name in (or, as it was in the original case, to remove a certain guild's name)
So, for the most part it looks like what this user has been doing has been good: they've been giving the wiki images it didn't already have, and if he gets to stick his name in as "bragging rights" for helping the wiki, so be it.
However, I reviewed his edit log and he removed some existing pictures in order to replace them with his own. That's a very clear bad practice, and so I have temporarily suspended this user until we can have a quick conversation and make sure they understand the rules.