The "Windows Photo Gallery" application bundled with Windows Vista supports a full-screen slideshow mode that sometimes tries to be a little too smart about choosing an optimal screen resolution for slideshow viewing. Specifically, the slideshow viewer may decide to reduce the screen resolution for full-screen viewing when invoked and doesn’t expose any obvious way to override this default behavior.
For most people this is not a huge problem (if they notice it at all). Discriminating viewers may note a degradation in image quality. But you really run into a problem if your video adapter is driving a display device that (a) isn’t recognized by plug-and-play (thus defaulting Window’s knowledge of your dislay’s actual capabilities to "Generic PnP Monitor" which is assumed to support a wide variety of different video modes) (b) doesn’t actually support the display mode automaticlly selected by "Windows Photo Gallery" for full-screen slideshow viewing.
In my case, this Vista box is using an NVidia Quadro FX1000 (a dated but still kick-ass video adapter) connected to a Samsung DLP HDTV which I’ve configured for full 1080p (1920×1080 @ 60Hz) viewing on the desktop. However, when I flip to slideshow mode I’m toast – the Samsung supports only a view different display resolutions and the one chosen as I enter slideshow mode is not supported. The display flickers and then bluescreens (Samsung video input not detected NOT a Vista BSOD). So for me on this particular PC configuration slideshow just doesn’t work out-of-the-box. Parenthetically, the standard Photo Viewer screensaver bundled with Vista is just a wrapper around Windows Photo Gallery’s slideshow mode so it too is busted for this particular configuration.
Luckily it’s not hard to fix.
Refer to the Windows Knowledge Base Article 930102 for specific details.
Add the DWORD value WinSATScore = 500 (decimal) to the HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows Photo Gallery\SlideShow key in the registry to instruct Windws Photo Gallery to use the desktop display settings when switching into slideshow mode. This solves both the image quality and the unsupported display resolution problems.