Welcome to us. This is the bestest place in the interweb and we all knows it How ar you managing with posting pics of your ride? If you go to the "go advanced" icon and then go to the "manage attachments". Browse your PC for the pic you want and upload it. Close that window and hit "submit reply". This will post a pic(s) to your post.
For the avatar, you'll need to resize your favorite pic to the standard required.