Use embeded images as snippet thumbnail on blog Options

[ProFanz]

Hello, I have a blog (profanz.com) and I recently decided that all of my writers and myself will start using embeded Getty Images. They are free and legal to use. I'm editing old posts but on the main page the new embeded images are not showing up in the article snippet thumbnails. Currently it's set up to look for:

'data:post.firstImageURL'

I need it to be able to pull a pic from a code like this:

<div class="getty embed image" style="background-color:#fff;display:inline-block;font-family:'Helvetica Neue',Helvetica,Arial,sans-serif;color:#a7a7a7;font-size:11px;width:100%;max-width:594px;"><div style="padding:0;margin:0;text-align:left;"><a href="http://www.gettyimages.com/detail/2669127" target="_blank" style="color:#a7a7a7;text-decoration:none;font-weight:normal !important;border:none;display:inline-block;">Embed from Getty Images</a></div><div style="overflow:hidden;position:relative;height:0;padding:71.212121% 0 0 0;width:100%;"><iframe src="//embed.gettyimages.com/embed/2669127?et=Cs7bF_f1Q1BVwU0L6qnIeQ&tld=com&viewMoreLink=off&sig=NhQO1K9F7P8iUkCjXapfa-EBBi04zNDuwhPKDL4IMDM=" width="594" height="423" scrolling="no" frameborder="0" style="display:inline-block;position:absolute;top:0;left:0;width:100%;height:100%;margin:0;" ></iframe></div><p style="margin:0;"></p></div>

My HTML abilities are very limited, any help would be greatly appreciated. Thanks.