Hello, thanks for messaging.
You are using Flexslider, but it is built into your theme. This is not related to this plugin, which is also using Flexslider but not the same one that you are using.
Fixing that is unrelated to this plugin, so I’m going to mark this support ticket as resolved.
The issue that you are having though is unrelated to the slider itself. WordPress creates attachment pages for media, including your slider images. I would look at a tool to disable attachment image pages. Some SEO plugins allow you to disable those pages, by having any URLs redirect to the main page that the images are on.
I hope that helps!