A few weeks ago I was trying to link to one of my blog posts from Facebook and Google plus. So I entered the blog post url on my Facebook wall post and I noticed the image was not ‘pulling’ and showing the way they usually do when you type an url in Facebook. Instead I got a 403 Forbidden error where the thumbnail image should be. The same happened when posting to Google Plus.
I know this issue is very specific but it drove me nuts trying to figure this out. And I could not find a solution from any of my searches which had to do with this particular task.
I had selected the Post name in my Permalinks Settings. But it turned out that the Permalink setting needed to be adjusted to include the word ‘Blog’ in it. So, in a multisite setup, the way it worked for me was to have the sub-site configured with a Custom Structure, like so:
The main site already had the word ‘Blog’ in the Post name setting, so no adjustment needed there.
This adjustment allowed WordPress to display the images when linking by url in sites such as Facebook or Google+.
Hope this helps =)