I can't send photos to people that don't have iPhones?

Recently I exchanged this iPhone for some reason, and got a new one. I recently I noticed I couldn't send photos to people that don't have iPhones. I'm with AT&T & I'm on the go phone plan, & before my mom used to show up 4G now it doesn't say anything.

Usually that means something in your settings was turned off. Like your 4G an sending pictures. Apple can fix that in a matter of seconds.