Buttons have info cramming illness
This week I have dealt with folks that have created design elements without giving thought to how they or their users would use these elements. The oddity in the three cases was creating a design that used image buttons with text. The size of the button's was fixed with the design. In all three cases one or more of the buttons tried to cram way too much text on to the tiny space. The buttons were unreadable.
Graphical buttons demand forethought. They should only contain one or two short words. Graphical buttons should be clear and easy to read. If the words on buttons are more than one or two words you and the user may be better off using text links. A good button would be "Animals 2001" not "Emprical Study of Animals in Tropical and Non-Tropical Environments - 2001". To convey the full text of the information you may be much better off using headers to structure the information, in this case using "Animal Reports" and "Emprical Study of Tropical and Non-Tropical Environments" then list the years offered in buttons or in a list. This provides much better scanning and can help break the information in to more scanable chunks.