Comment photo not updating

I have noticed that when i “Like” a post, i see a image of a silhouette person next to the info about the post. This image is fetched from:
https://fbexternal-a.akamaihd.net/safe_image.php?d=AQDuI1Ol1yQmMuMX&w=154&h=154&url=http%3A%2F%2FCraftersU.com%2Fwp-content%2Fplugins%2Fall-in-one-seo-pack%2Fimages%2Fdefault-user-image.png&cfs=1&upscale”

Since the name of the plugin “All in one seo pack” appear in this link, and i do use that plugin on my page, i tried to change the settings in its “Social Meta” settings, but that only changed three of the posts photos. One of them turned into the Google+ icon for some strange reason. But all the others are still showing that boring gray silhouette. What is going on?

https://wordpress.org/plugins/facebook-button-plugin/