The socialize plugin was working fine with a "Call to Action" box until i had to change all image filenames (and title/alt). Afterwards, facebook "like" stopped appending the product images.
The few products that remained unchanged look fine on facebook, with featured image and everything.
Google+ works fine, the issue is only with facebook.
I've tried reinstalling the plugin but the problem remains.
The changes I made are rather recent - happened during the last few days.