SEO not recognising images

Justy added the Yoast SEO plug in to my site and noticed it’s ranking my SEO as OK on this page, (its the first page ive tried).

It says the page contains no images, yet it is actually an image gallery.

Can anybody advise?

Screen shot: http://i61.tinypic.com/10i6ovd.jpg

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