I am getting curious now.
What would be the purpose of having a bot that posts parts of previous posts and includes a 1x1 pixel sized image that is not visible? If it was an attempt at spam would there not be links or something visible?
Riverrock,
You can see usernames registered in the last few days with names like "Claudette381" or "Curtis532" and so on, making posts that just include this little image file and snippets of previous posts on the same thread.