Imessage photo messages

Hi all,

Myself and my partner have just upgraded to IOS 7. Me on Iphone 4 and partner on Iphone 5.

Since the update we are unable to send photos to eachother over imessage, they say they have send and delivered but nothing at the other end.

Our settings match those from before this problem. Anyone know if this is a reported bug or of anything which may fix it?

Thanks in advance.

Dan