What is Resolution - Definition of Resolution:
Definition:
Resolution is the term used to describe the number of dots, or pixels, used to display an image. Higher resolutions mean that more pixels are used to create the image, resulting in a crisper, cleaner image.

Native Resolutions:
All LCD screens can actually display only a single given resolution referred to as the native resolution. This is the physical number of horizontal and vertical pixels that make up the LCD matrix of the display. Setting a computer display to a resolution lower than this resolution will either cause the monitor to use a reduced visible area of the screen or it will have to do extrapolation. This extrapolation attempts to blend multiple pixels together to produce a similar image to what you would see if the monitor were to display it at the given resolution but it can result in fuzzy images.

Here are some of the common native resolutions found in LCD monitors:

14-15 inch: 1024x768 (XGA)
17-19 inch: 1280x1024 (SXGA)
20 inch + : 1600x1200 (UXGA)
17 inch (Widescreen): 1280x800 (WXGA)
19 inch (Widescreen): 1440x900 (WXGA+)
20 inch (Widescreen): 1680x1050 (WSXGA+)
24 inch (Widescreen): 1920x1200 (WUXGA)
30 inch (Widescreen): 2560x1600