Do you mean that you want to send picture messages (MMS)? As well as the correct settings on your phone, which you can get by texting WEB to 40127, the service also needs to be provisioned on your account. Because it's a bit of a legacy service and chargeable, it's normally switched off by default until you request it. 191 and LiveChat aren't always very good at this, so you're probably best off hanging on for the Tech team here.
There are non-chargeable alternatives to MMS: Whatsapp (and other similar services), Vodafone Message+, which is a variation of the recently introduced Rich Communications Service - this will replace the old SMS app on Android device at least in due course, or email. These alternatives will use data, of course, but there's no additional cost as long as you remain within your allowance and aren't paying per mb on PAYG.
