I wonder if your browser is set to not display photos that come from a
third party site? Some people will upload their pictures to another site
(such as Photobucket) and post the link in here. Most of us see the photos,
as the link loads the pic in our browsers, but I know you can set it to not do
that. For instance, I used to set it to reject photos from sources other
than the originating website so that if I got porn spam, at least the photos
wouldn't make it to my browser. I used to get a LOT of empty messages!
But that was years ago, so I don't really remember where the setting was.
Probably under Preferences or Tools .. depending on the browser