I am using Windows 7. I had tried Media Center in Vista but it was mostly an unpleasant experience. Win 7 was no better and I wrote it off. Then I discovered Media Center is meant to be manipulated with a remote control rather than a keyboard and mouse. After dithering for several months I ordered a remote for Windows Media Center. They seem to run between $12 and $25. I don't know anything about them, chose the $18 variety.
Oh my! I opened my picture folder. I quickly learned I could make the picture the size of the screen which in my case is 22" - which translates to 18.5 by 12. I quickly spotted details I had not noticed before. A little more playing and I found I could zoom in more and then once more. I can pan the picture, left, right, up and down. It's great for group shots.
A long mysterious group shot containing quite a few relatives now can be seen to have background details virtually invisible before which might provide clues to the location of the event. I was able to study faces a lot better and have tentatively identified two more people.
Imagine doing this on a large flat screen television. I did not notice any distortion in going from the standard size from full screen. Who knows what one might discover.
You can also view videos, play music, even view and record tv assuming you have a tv tuner or have cable hooked up. I did run into trouble when I tried to access photos on my network attached storage which works well with other programs. I have not had time to look into that.
Media Center is part of the OS in Vista and Windows 7.