Thanks, looks like everything is almost done. I managed to play around with positioning of the code in the page.php to set the image inside the content field, which still allows the sidebar to remain fixed and spaces everything nicely. The only problem is that I only have one page that I've created, and that's the "about" page. Where can I add a custom field to the home page, i.e. the first main page of the blog. I looked around in index.php, but if i put an image there, it shows up on every page, not just the blog I want. I have one site (ecclecollective.com), with two blogs (/beforehecansee and /whoislikegod). Whatever is done to the index.php affects all of it. I just need a banner on the first page of each blog, and on each additional page (which is only the "about" page, and I've got that to work).
Secondly, even when I add a custom field to a post (not a page), the banner isn't showing up. I need the banner to be present everywhere on every page of the same blog, whether its /beforehecansee, /beforehecansee/about, or /beforehecansee/2013/03/01/in-the-in-between.
I know if I had all three sites with their own directory, this wouldnt be an issue because I can just put the image in the index.php file and be done with it, but since this is WordPress's multisite, which shares one directory, I have to be a little more cunning to be able to have three different sites display three different things.
Thanks again for your help. I'm learning a lot and appreciate your time.