Changing link preview(?) image and description

I'm trying to change the preview stock image and description for when you copy and paste link to a site (note i'm using an HTML template). I see the stock image files and text in the meta tags in the header but when I change the images and description, it still appears the same when I paste the link on a Facebook post. Does anyone know a solution? Maybe I need to edit something else besides the meta tags?

Here is a Preview image

Here is a sample. Also note, the comment for this section of the code was labeled Facebook and there was a another section labeled "Twitter". I've tried changing the twitter section too, but its still the same result.

<meta property="og:locale" content="en" />
    <meta property="og:type" content="website" />
    <meta property="og:title" content="Soundcast" />
    <meta property="og:description" content="Podcast Responsive Theme" />
    <meta property="og:url" content="" />
    <meta property="og:site_name" content="Soundcast" />
    <meta property="og:image" content="" />