Dick; If you are referring to the "broken icon" at the end of a message ... it means that someone has attempted to include a picture in their post with an incorrect Optional Image URL ... or for a URL that does not exist.

If posters would preview their messages that are intended to include images ... and when they see that "broken icon" in their preview ... it would be a good bet that their intended image will not be seen by readers in their final post either ... and they can find out and fix the problem before posting.