One way to add a background photo to any custom Tumblr theme is to embed a simple CSS tag at the right location in the theme's HTML code.

While you can also insert additional code to further customize your background using the Edit HTML tool, making basic changes to the background do not require you to write code.

Following is a sampling of HTML color codes used in HTML tags for setting background and font color. Colors are coded as red, green and blue intensities in hexadecimal notation (see hex chart ...