[Forum] Swap "new messages"/"no new messages" images.

[Norway174]

Shame this isn't XenForo. Would have been able to make that change in 2 seconds. And I know of a very good, and flexible theme for that forum software. :P

Actually did make an XenForo forum for another community a little back. Think it turned out pretty well.
But unfortunately, that forum isn't free. :/