A friend needs help with a blog, the problem is that when he posts something from blog to facebook he can't get the right thumbnail, the problem is that at facebook debugger the image that it gets is the thumbnail of the picture. The blog is on blogger and has been used a plugin for the share buttons(I don't know which plugin). Sorry that i don't post some code to help you better, but I'm just searching in dark to find a solution.
EDIT
I added these but again i have the problem with the picture, fb debugger says its too small. The data:blog.postImageThumbnailUrl
is responsible for the size (72x72 generates). Is there a way to change this?
xmlns:og='http://ogp.me/ns# at the end of the html tag
<b:if cond='data:blog.pageType == "item"'>
<meta expr:content='data:blog.pageName' property='og:title'/>
<meta expr:content='data:blog.canonicalUrl' property='og:url'/>
<meta content='article' property='og:type'/>
</b:if>
<meta expr:content='data:blog.title' property='og:site_name'/>
<b:if cond='data:blog.postImageThumbnailUrl'>
<meta expr:content='data:blog.postImageThumbnailUrl' property='og:image'/>
<b:else/>
<meta content='https://fbcdn-sphotos-d-a.akamaihd.net/hphotos-ak-ash4/487911_488950037808372_1165794149_n.jpg' property='og:image'/>
</b:if>
<b:if cond='data:blog.metaDescription != ""'>
<meta expr:content='data:blog.metaDescription' name='og:description'/>
</b:if>