Disable any proxy settings on Chrome. If it's not that, then there's a "Welcome to nginx" redirect/hijack virus that you may have picked up: Try a virus scan with: http://www.malwarebytes.org/
and I thought Chrome was secure Ugh. I don't wanna reboot and do all of that. Ima just run a scan. My Celestia I hate Symantec
Looks like Rarit had the same issue, clearing his history seemed to do the trick (seems to solve everything nowadays): http://www.everypony.com/forums/showthread.php?8568-Derpibooru-issues
Oh yeah by the way sometimes I get a MLP wallpaper or two on a Equestria Daily Wallpaper Compilation.