Add image to header region.

Good day,
I have two questions, dont think its really hard for developers but kinda confusing for the beginner. I have Drupal 6.13.
In Acquia Slate I would like to add image to the header region(i dont have a slogan or search) and have it to be displayed on all pages except front page. I already have the front page I want but would like to see additional image on header when I click any of my primary links.
Could you please advise how I separate whats displayed on front page and whats on other pages.
Thank You.