Author URI: http://allanjosephbatac.com/blog/
As soon as someone Likes your post, Facebook schedules a spider/crawler to automatically scrape the page. The crawler looks for an image to grab. If your blog post isn't helping the crawler find an image, Facebook will use the first image it will find (based on a complex algorithm).
Use the "Open Graph protocol". It is well-documented over here: https://developers.facebook.com/docs/opengraph/. I know it's a lot to cover and it's not easy for a non-programmer to understand it. I haven't seen a good WordPress plugin that will help the Facebook crawler choose and pick the right image but if I do, I'll let you know.
Absolutely. I just pray to heaven everyday that someone out there buys me a coffee. ;)
This plugin automatically adds the Facebook like button so you don't have to manually do it for each post. There are also options to customize the look and feel.
The Send Button allows your users to easily send your content to their friends. People will have the option to send your URL in an inbox message to their Facebook friends, to the group wall of any Facebook group they are a member of, and as an email to any email address. While the Like Button allows users to share your content with all of their friends, the Send Button allows them to send a private message to just a few friends.
Facebook has this space to show faces of Facebook members who liked your post or page. If you disable show faces in the settings it will get rid of that space. The options on the plugin also allows you to do that.
Follow me at Twitter @ajbatac or send me a mention. I'll reply as soon as I get it.