What do you want to achieve? do you want create a chat apps or something?
1.it depend what do you want to achieve, if you want to create a chat apps, and send an image on realtime, you could send it with
http request and notice the other user with socket message
2.delivery report can be achieved with server side code, you can tell message is delivered or not by :
a.checking is other user socket session is active or not
b.is activate send the message, is error or not
c.is error message is not delivered