How do I brwose a particular directory?

This in the context of a skin using an addon that lets you change the background image on the home menu. I select change background image > multi-image > and shows some folders, none of which I want to select, so how can I go to the ones I want? The arrow on the top (to go to the upper level folder) only goes as far as within the skin, and I want to select a location outside of it.