[support] gallery images are opening in very small size

Hello everyone, I have set up media_gallery with colorbox in http://www.mountvilleresorts.com/. gallery is working fine but gallery images are opening in very small size. you can see screen shot at http://i.troll.ws/ccd2a3c5.png but after opeing again images opens in right size. what is wrong with galleries so images are not opening with proper size at first? thank you