OpenGraph for Blogger

og.html

<!-- Begin Open Graph metadata -->
<b:if cond='data:blog.pageType == &quot;item&quot;'>
	<meta content='article' property='og:type'/>
	<meta expr:content='data:blog.title' property='og:site_name'/>
	<meta expr:content='data:blog.pageName' property='og:title'/>
	<b:if cond='data:blog.postImageThumbnailUrl'>
		<meta expr:content='data:blog.postImageThumbnailUrl' property='og:image'/>
	</b:if>
<b:else/>
	<meta expr:content='data:blog.title' property='og:title'/>
	<meta content='website' property='og:type'/>
</b:if>

<meta expr:content='&quot;en_US&quot;' property='og:locale'/>
<meta expr:content='data:blog.canonicalUrl' property='og:url'/>
<!-- End Open Graph metadata -->

OpenGraph for Blogger.md

Adding Open Graph metadata to Blogger is easy. Simply copy the code below and paste it into your template after the <header> tag.

A couple notes:

• og:locale Should probably actually reflect the blog's locale instead of just being a hardcoded string. Unfortunately, Blogger only gives us en-us with a hyphen, instead of an underscore, so that won't work.
• If you're using your blog as a personal profile, you may consider changing the second og:type from website to profile and adding your personal information
• og:image Is only supplied if Blogger finds an image in the current post. However, not supplying og:image is invalid. You could provide an alternate image of your blog logo, or a Gravatar.
• If you do something cool with this, I'd love to hear about it. pathawks@shortmail.com

I added og:title and og:description to the top, but when Blogger generates each page, it automatically creates another og:title and og:description based on the contents of the page, and Facebook take these because they are further down.

How does Blogger generate the two tags or how can I override them?

Yes You can, Just remove
<b:include data='blog' name='all-head-content'/> from your template

how to do meta tags by taking a thumbnail image on blogger static page

Thank you very much, this helps a lot, I didn't know how to do it.

I think would be nice to have a "else" for this "if":
<b:if cond='data:blog.postImageThumbnailUrl'>

</b:if>
So we could put a default image too