Remove images in post area.

Hello! So I accidentally uploaded my comic images into the “post section” along with the featured image section. I was not aware that the featured image section was all that I needed and now I have double images of my comics in each “page”. An example can be found here:http://revfitz.com/comic/issue347/ This would not be a big deal if I did not do this to almost 400 comics. To be clear, this is not an issue of the featured image showing up twice, but rather both the featured image and an image in the post section. Is there a way to remove these in bulk?

Also: Comic Easel is great! I am a huge fan of it and love the plugin, thank you!