I was wondering,how much posts do one nid to get promoted to Frontier Brain and Pokemon Master? Ohyamhow do I change my pic???

Welcome to the forums

Frontier Brain is a moderator status. You can't get that rank unless you are chosen by an admin to moderate the forums. Same with Gym Leaders.

Pokemon Master on the other hand, is a rank you get by posting constructive posts.

Bug Catcher - 0 Posts
Pokefan - 25 posts
Pokemaniac - 50 posts
Cooltrainer - 100 posts
Pokemon Master - 250 posts
Pokemon Professor - 500 posts

http://psypokes.com/forums/psyfaq.php#1

To change your avatar, or the picture by your name, you have to go to your profile(there is a link at the top of the page), scroll down to the bottom, and there is an avatar section. You can choose an avatar from the already premade ones by choosing the avatar gallery, or upload your own from your machine. You can get people in slateport market to make you avatars as well.

If you have any other questions, you can ask. ;D

Also:
2500-????
Something that I studied from other members such as Rubypoke and Flarey.