It could be a few things. First we want to make sure you can access the internet (i.e. load web pages). Task killers and antivirus have been known to interfere so I would uninstall any apps such as Advanced Task Killer and Lookout and powercycle the device, if the issue persists you could try clearing all you text message history. If none of this resolves your issue I would need to know specifically what happens when you try to send the picture.