If you go to Settings, there is the Edit Avatar. Then there should be a drop-down list. It has all sorts of avatars, like every Pokemon and shiny sprite, every trainer sprite, official Pokemon art, some smash brothers ones, Pokemon plushies. Mine was under Trainer sprites (Hoenn) I believe
I got the most excited about the whole outside the pokeball thing when I realized that they showed sprites as shiny if the Pokemon was. That's really what made me turn to shiny hunting. I fell in love with how special it looked, and now I love to find shinies.
Cute avatar :3 I think I liked the Gold/Silver remakes the best. The fact that your pokemon walk with you was really attractive to me, and I love the Pokewalker! Now I get to have my baby, Charcoal, with me all the time! I feel really uncomfortable when I don't have him with me. Like if I forget him at home or something.