First image not centering

I believe this has to do with the index page, because when I click on the individual page links, all of my images are perfectly centered.

I’ve tried going into my .css, but I don’t see the problem. Any ideas?

P.S. I know the problem is related to this plugin, because when I uninstall it, there are no alignment issues. Please help, because I like the plugin so far 🙂

http://www.partialtopink.com

https://wordpress.org/plugins/wordpress-seo/