Problem with Facebook share

Hello. My wife has a blog and the home page has the most recent posts. At the bottom of each post, social media share buttons. Facebook is included. When you click to share the post to Facebook the window that opens pulls some random picture from within the home page and has nothing to do with the post you are wanting to share.

Am I using this wrong? If not, please help me fix the problem.

https://ww.wp.xz.cn/plugins/ultimate-social-media-icons/