Images and skins/themes

[1] How do you make an image appear to the left or right side of a category or board name (for an individual category/board, I mean - but I'd also like to know [2] how you edit the image to the left of each board)? And also, [3] where do you go to create your own skin/theme for your forum, and, [4] if it's not against the rules (let me know if it is so that I don't make that mistake), how do you edit and where do you go to edit an already-made theme (without taking away the credits)?

Ya, i was also wondering if u can create and upload your own skins because id rather not have mine the same as another site, im running phpBB3 if that makes a difference, thank you for the help