Hi HostingPlace, you can actually tell Facebook or Google+ which title, description/snippet and thumbnail to use for link preview. You need to include a few lines of Open Graph tags together with meta tags into the header of your HTML document.
Here's a comprehensive guide on how these tags should look like: http://www.xldstudios.com/add-facebook-preview-image-title-and-description-with-the-open-graph-protocol/
Let us know whether the above solutions works for you. I tried this on one of my clients' and it worked. For my blog, both Google+ and Facebook is pulling the right information out every time so I guess kudos to Chris Pearson, the creator of Thesis theme, who got this right.