Why make a big deal out of it just because he wants to? It takes two people to "argue". Just say "no" and talk to him about other things.
You know, DJ, please keep in mind what "dating" is supposed to be about...and nowadays that includes the incessant 'text-frenzy' that seems to skip so many common courtesies you would normally expect and GET in real life.
Remember that the reason you're spending time getting to know someone is to make a judgment about how compatible you are. You're deciding if you can live with the good and the bad that is this person's personality enough to "forsake all other possible partners" in life.
That's pretty serious, isn't it? Make sure you're willing to judge.
It's NOT the goal of dating to make a list of the things you don't like and try to change them because you've spent X-days working on it...not at all. A common practice and a consistently bad idea.
How much better would it be for you to just make simple judgments about your compatibility? When it's a bad match, wish him well and move on without engaging in all the drama.
Dating is nothing but a chance to realize that when the "nice-nice" stuff finally subsides and the normal moody-temperamental-short-tempered-sometimes-still-nice-whatever guys shows up...then that's who he is. If he can blow up a simple thing like not getting his way about this pic, how much more crap can you expect to come down on you over dumb stuff?
If that's OK with you, call it a good match and start making wedding plans.
If it's not OK, wish him well and move on. No drama needed.