I just today removed all of my blog post images and uploaded new refreshed images. I then relinked all of my blog posts images to the original post Image Control. Now, my blog preview page no longer displays the thumbnail images. All of the posts are properly linked to an image and there are no additional changes on the site. Please review the blog overview page: http://www.formtools.us/blog/form-packs/
and the individual post page (with the linked image): http://www.formtools.us/import-and-export/

Again note the blog overview page and associated image thumbnails were working perfectly before I deleted, refreshed and relinked my post images. The Blog Post Pages are using a standard Image Control.