Blurred wallpapers on tablet screen

When I set up a wallpaper on tablet (color) screen it's always slightly blurred.
I speak about high resolution wallpapers like 3800 x 2750, 2560 x 1600 , 1920 x 1200 etc.
It was always and it's not after an update or something. When I see a picture in a gallery it's perfectly sharp and not pixelized but when I use it as a wallpaper it's slightly blurred and pixelized , you can't read a small font for example that you can read in gallery.
The same wallpaper on e-reader screen aside from being black&white is very clear and not blurred.

Do you have this problem too?
Do everyone has it?
Maybe I should use a specific resolution to have not blurred picture?

According to the post http://www.entourageedge.com/forums/...tom-Wallpapers, the optimal dimensions for an LCD wallpaper image are 1195x1024.