When I receive pictures from one particular person, they arrive as an empty square with a red x in the top left corner. What can I do?
One likely reason is that "one particular person" is forwarding Incredimail messages, as messages instead of attachments. Are you seeing "Incredimail" anywhere in those emails? There could be something else involved, but if you can respond in more detail about what you actually see in those emails (or the headers), that would be helpful.