A user on italian forum complained about the thumbnails for images doesn't appear in category view but are present in home page.
see this: home page http://persbaglio.wordpress.com/ with images
category page: http://persbaglio.wordpress.com/category/ah-ah-ah/ with no images.
I didn't find any option to change this behavior. Is this a limitation - by design of the Digg 3 Column theme?