Character Help

[Gaming24/7forthefunofit]

I am currently using RPG Maker XP: Postillity Knights and i wanted to change my main character. I then imported at the "resource manager" tab and switched my character in "database" tab and inserted my charcter into "Character Sprite" . But when i played my game, i noticed that it is not transparent and it is not the right size. How do i make my character transparent? How do change the size of my character and what is the best size? Should i switch the format of my character into .png or which format is best? Help PLEASE and THANK YOU!!!

[WarxePB]

Well, I'm not sure how to convert it to the right size, but to make the background color transparent: When you import the character set, left-click the background color, then hit OK.