unless you want to see the picture, May times someone will post a message in the suject line, then place a picture in the url image box. The result will still be the little red X in the cirlce, but you want to open it to see the picture.

So....again, the red X just tells you no text was placed in the "message" box. It may still be worth opening if the subject line indicated something new to see.

The icon of the camera indicates there is a photo included.