I have an idea for a plugin that connects to a servers flickr account. Then ingame you will type a command like /flickr and a screenshot will be send to the servers flickr account
Where? To get a screenshot of the client's current screen, without GUI, the server would need to render the map itself, which is not ideal for just a screenshot.
http://www.minecraftforum.net/topic/90080-tectonicus-v202-18-support/ but as you say it it's on the map render it happens... daam would be a nice feature