Why image resolution at 96 px/inch?

[Theo Dibbits]

I like the clarity and sharpness of the UK pictures you can use as wallpaper in Windows 7 so I decided to have a look at how they are formatted.
The first thing that struck me was that they are not sRGB but either Adobe RGB or ProPhotoRGB

But even more puzzling they are all formatted at 96 pixels/inch.
So I checked the folders for the other countries (there are some stunning images) and they are the same.

Windows standard wallpaper images are sRGB and 72 px/inch but don't look as sharp.

Why? I have allways been under the impression that a monitor has a native screen resolution of 72 px/inch.
Does this mean that if we format our pictures for digital projection at 96 px/inch we get a sharper image?

Theo

[John]

It depends upon the native resolution of the devices concerned. Monitors display at 72 or 96ppi and if our images are that size then no interpolation will be necessary. So a 1024 x 768 pixel image on a similarly sized display will be as good as you will get. The ppi has usually been 72ppi but maybe some Windows 7 machines, now often 64 bit, display at a higher resolution.

[sunsworth]

The DPI for wallpaper is irrelevant. The wallpaper doesn't know if it's being used on say a 17 or 24" monitor - and at a given screen resolution in pixels the 17" monitor will have a greater dpi than that of the 24" monitor. The only factor that should be important is the dimensions in pixels, and they are dpi independent.

The wallpaper could be 1280 pixels wide at 1 dpi, but it would be displayed identically to the same wallpaper at 1000 dpi.