I have just checked my bill and k have been charged for picture text sent to Canada and america.What's going on I've noticed quiet a few people with the same problem.the only picture text i send is to my wife's forging mobile and my dads Virginia mobile.
Similar experience, I matched dates and times to text or picture messages inadvertently sent to one of my contacts for whom I had only a (UK) email address, and no phone number. There is a very brief warning on screen that the message is being converted to multimedia message (MMS). It seems that the text messaging system (whether on the phone or at the provider is not clear) automatically does this and attempts delivery by forwarding the MMS through a remote email server, which seems to be in America or Canada. The billing system assumes that MMS are picture messages and charges accordingly.
I explained this to a customer service person, after she asserted at tedious length that these were charges correctly applied, to a message that I must have sent to an American contact, etc. etc. When I eventually got a word in, she recognised and confirmed the scenario I outlined above, and agreed to waive the charges this one time.
There is no warning that this might happen, and no reason to believe that sending a text from UK to a UK email address should incur an international message charge, so I believe such a charge is unreasonable and should be challenged every time. To avoid it happening inadvertently I suggest ensuring that all contacts saved on the phone should include a phone number - if necessary a dummy one. (Ofcom provide a list of unallocated numbers for use in drama productions; I assume they do not connect and so are not charged)