Recent question: How did I set the page background color to match the image?
The answer, seen here, is superdooper easy, and though it uses Dreamweaver, you may find similar color pickers in other applications.
Also of note, I quickly make these galleries with Photoshop's Web Gallery automation tool. Then I open up each page to edit the title or background color. I know there are better ways, but for now this works for me.