If you mean MMS messages then you may need to check your carrier's MMS settings on the phone. They may need selecting and activating in the message settings.
Personally, I find it easier to send pictures via WhatsApp but that would rely on a Internet connection and the recipient having WhatsApp too.
Just seen your message about being able to receive them but not send. If you're on contract you may have a spend Cap that's stopping you from sending them... Spend Cap on your tariff as MMS are normally chargeable. If your Spend Cap is set at zero then this may stop your MMS sending.