My featured image no longer resizes

I’m not too wordpress savy, but I have recently been having trouble sizing my featured image. All of my older posts turned out just fine when I resized them, but now when I attempt to size my feature image now, it doesn’t work. It still appears as a default 663:189 – and this size isn’t very complimentary to many of my photos. this problem started 2-3 days ago, when i updated my wordpress, could this be an update issue? help!

http://wordpress.org/extend/plugins/featured-image/