Not to jump on the Microsoft-slagging train (be that they deserve it), I tried to associate image files with an excellent (well, generations ahead) picture viewer in Vista.
Turns out there’s no easy way to say “use this to view these image types”, even though, after about 17 years of development and buying-up of any company that has good ideas, they should have realized the dreaded 3-letter suffixes they made standard are of some importance to the functionality of a computer.
The staggeringly mind-blowing abysmal functioning of the Control Panel/Default Applications utility makes that clear as mountain dew from Tibet. They actually mean for users to click one file extension at a time, each time clicking a button and selecting a program.
I’m not kidding. Check for yourself. “Do it! Do it NAUWW!”. The power of Arnold compels you.