You have a choice of colours of the Yahoo! logo on your page header. To use an image as your tab background, follow these steps:
A diagram of the Yahoo! My Telecom page, a list of customizable elements, and a colour palette opens. Note that there are five customizable areas that outline in yellow as you roll over the diagram.
Note: You can abandon your changes at any time by clicking Reset. This returns your tab to the colours of the most recently saved theme.