After selecting character, game graphics freeze

snschl

I've had this for a few days now, but it's becoming more frequent. Whenever I pick one of my characters (doesn't seem to matter which), the game logs in normally and then the visuals freeze. Not the game itself; I can still hear myself swinging around and summoning my horse, but the graphics remain like this:
Screenshot
And all I can do is shut down the game and login again. If I try to resize the window or maximize it, the game crashes.

It doesn't happen every time, but it just happened five times in a row.