Can not delete (thumbnail) images on front page Daily Theme

I am working with the Daily Theme. I am trying to replace the images (thumbnails) that I have put on the front page with new ones, however while I have deleted the featured image and the image in the post, the images are still appearing on the front page. When I add a new image, the old image remains. I am using Daily Theme 4.1.7/multisite install/WP 3.3.1. Any suggestions would be appreciated.

Thanks.