Works, but difficult to update thumbnails (was expecting it could be done all at once)

The 'use snapshot of current tab as thumbnail' option only works about half of the time. For instance on Vudu, Capital One, and DepositPhotos, the button just doesn't light up when I go to their homepages. Because your plugin isn't grabbing any kind of thumbnail at all from those url's (not just the page I want to use after I login to the sites), I'm left with several blank thumbs for important links. Please look into and resolve this issue. It's been happening for over a year. I was hoping you would figure it out and released an update already.