Why can't I receive or send pictures or get group texts?

[BNP20]

So I have a Samsung Galaxy Alpha and it won't let me send picture messages while I am on my WiFi. It also won't allow me to download group texts or send a text unto the group text. The only time I can do anything is when I have 4G. Also I don't have a tab called network mode. I have look for it and I can't find it!

 

[B. Diddy]

Welcome to Android Central! MMS (Multimedia Messaging Service) requires mobile data, not wi-fi or voice signal. MMS is used to send photos or videos via texting, as well as group texts.