Hi - Your theme is using a PHP program to create thumbnails on the fly. They are not being created.
The image code for the home page's upper left corner is:
<img class="postimage1" alt="That’s your wife?" src="http://thesporg.com/wp-content/themes/bignews/thumbs.php?src=http://thesporg.com/wp-content/uploads/2011/07/cameron_diaz-500x375.jpg&h=250&w=280&zc=1">
The full sized image, http://thesporg.com/wp-content/uploads/2011/07/cameron_diaz-500x375.jpg, does exist. Because the image being reduced in size to a thumbnail by thumbs.php exists at the URL it is supposed to, this means either thumbs.php file is not found wher it's supposed to be at http://thesporg.com/wp-content/themes/bignews/thumbs.php - or if it is there, something about the way it is configured is not correct.
I'd start by looking at the Big News theme options settings in the WordPress Dashboard. They would be found either under Appearance, or some themes install a menu section of their own. See what is offered for thumbnail configuration.