Kirby, the correct way to reply to a VM (message) is by clicking the 'view conversation' button and posting it there, or I'll never know if you replied. Lol. XD
And to change your avatar, you'll need to go to user CP (It's on the navigation bar-- at the very left) click it, click edit avatar and you can upload/ paste the url of the pic. Oh and btw Profile pics only appears on your Profile (Well at least for PC) To edit that you'll need to click User CP, click the User control panel link and at the left there's a selection of different things and one of them is change profile pic and you can change it there. x)