Are you referring to photos being sent to you by text message? Do you have your data disable?
If so you will need to enable the data on the phone in order for the MMS to download. You can also try doing a network reset and see if that helps.
Is this only happening with specific contacts? Maybe the problem is with those contacts.
You can try doing a network reset on the phone and see if that helps, to do that go to Settings-> Systems-> Advance-> Reset options and select reset Wi-Fi, Mobile & Bluetooth.
Also, make sure your APN settings are correct, you can find that info here.
I also found sometimes if you have a lot of messages you sometimes get issues, you can try clearing the app cache and delete some older text.
If all else fails you might have to do a factory reset.