You can.

<------ See?

Had planned just to say this, 'many players already have their own in game user pic'

 So either for some unknown reason you haven't noticed this,they stopped allowing it now, or you do not know how to achieve it.

RealBigOleDummy 

But is your forum pic also your ingame user pic?

Yes xyz this is the same pic I have ingame. I change my ingame userpic several times a week actually. Its kind of a joke in my Clan actually lol.

guysensei21123 , I apologize for being so flippant in my reply to you earlier. I should have told you how to do it while here then.

Since you already have a Forum account its quite easy. At the top of this page click on your name and choose My Profile. When you get there just click on your picture THERE and choose upload avatar. Upload it from just about anywhere I guess but I use my Windows Pictures folder. When you go to the game it will be changed. Quite rarely , if you have the game open in another tab as you change it you MAY have to refresh the game. Thats it, thats all you have to do.

I don't use facebook but have been told you can change it from there also but I cannot confirm that personally. 

I have same problem my user pic is change here but not change in the game