If you throughly studied the very many settings of the Photo Albums -> Settings admin page and you still can not get the display you want, there is a way to make your customized CSS file.
To avoid overwriting your modifications when an upgrade of WPPA+ occurs, you should make a copy of .../wordpress/wp-content/plugins/wp-photo-album-plus/theme/wppa-style.css and place it in your Theme directory (for instance: .../wordpress/wp-content/themes/twentyten/ ) and edit that file to make your changes.
As soon as the plugin finds a wppa-style.css file in your active theme directory, it will load that one and ignore the original one. This also means that, if you regret your alterations, just delete the copy in the theme directory, and things are back to original.
By modifying this Stylesheet, be aware of the fact that the settings in the Appearence section of the Settings admin page have priority over what you put in the css file. So, if you want to set a background color in the css file, make sure the corresponding setting in the Settings screen is left (or made) blank.
Also, be aware of the fact that a new version of the plugin may imply changes in the 'official' css file that are vital for the proper functioning of new features of WPPA+ or may have impact on changes in the implementation.
As a guideline: Major revision changes (e.g. 2.x.x to 3.x.x etc.) as well as minor revision changes (e.g. 2.3.x to 2.4.x) will require that you revise your modifications, there will most probably be changes in the 'official' css file that you won't miss.
If you have a modified CSS file in your active theme directory, you will get a one-time reminder as soon as you enter any WPPA+ admin page after such an upgrade of the plugin.