Hello,
I'm having the same issue as here: http://wordpress.org/support/topic/circle-reveal-on-pics?replies=7
(My post has been delete 4 times, without anyone telling me that we cannot post for the same issue in the same topic. Scary)
My website is here: http://www.adlice.com
That happened (I think) when I used the CSS editor to test a CSS line (added/removed).
I tried to remove the featured image, reset it. Nothing.
I really have no idea of what to do to fix this, any suggestion? Is it a bug?