iMessage for iPod won't show pictures received from other iDevices

Hey,

For a while now, my iPod Touch 4G 8GB has not been showing pictures received from other iPhones/iPods. I can see a small image of it when I get a notification when I'm not on the iMessage app, but when I open up iMessage to see it, only the photo summary (The writing that was sent with the image). Sometimes that message comes with a red "!" mark. When I click that little mark, it shows a button that says "Try Again", as if I wrote the text and it didn't go through. If I click it, it sends that text again, but from me. And the thing is, it shows the photos I send to people! It's messed up! What can I go to let iMessage show photos sent to me again?