uniform size for header photos

hi Tom,
i sent you a number of questions re: making the header photos for categories the same–and SUCCESS!! i finally figured it out. it wasn’t as complicated as i thought it would be~~ just wasn’t understanding the interface.

anyway, now that i’ve done that, i was wondering if:
1) is there was a way for me to make ALL of those photos a uniform size across categories?–(i used GP Hooks)

2) is there a way that i can center the titles for the sidebar widgets?

3) i also wanted to center the category titles.

***i imagine there’s some coding involved for 2-3, but i wasn’t sure where to put that coding…

thanks for your help!!