Images with Captions Won't Align

I’m trying to make a row of images line up. When I add the captions, they stack, but when I take the captions out, they line up across the page like I want.

My site is https://www.thebusybibliophile.com. I’m on WP 3.7.1 with a genesis theme. What I’m trying to do is on an unpublished post, but I can copy the page source if that would help…

Any help would be greatly appreciated.