Good news for fans of mobile photography and social networking - Twitter has introduced MMS photo sharing in conjunction with UK mobile networks.It is pretty much as it says. It's an extension of the SMS service already used by Twitter for posting updates. If you've never used that way of updating your status, plenty have, with Twitter claiming it receives four million SMS messages every month. So the MMS service is likely to carry out swift business too.As of now, you can share photos on Twitter by including a photo in your message. Just enter the text of your Tweet as you normally would, attach a photo to the message and send to Twitter. That's as long as you are on the right network, which in the UK is a choice of Vodafone, O2 and Orange. We're surprised T-Mobile isn't here, especially with its close relationship with Orange. Perhaps that network will come on-board later.Obviously charges will apply for the service, so if you are within a (free) Wi-Fi area and can update via a smartphone, that's still the most cost-effective way. See the Twitter site for specific numbers if you do want to MMS.