When's a picture not a picture

Mobile network provider sent me an email saying I'd been sent a picture - No picture anywhere in sight, however there was a text document attached. Opened that and there was a rather smile-causing text message.

But how did O2 get a text/picture confused? And how was the iMessage (which was sent from One apple to device to mine) sent to O2 to then come to me from them as an email... My brain hurts...