What is VGA, SVGA, XGA...?

The Video Electronics Standards Assocation (VESA) has established a standard programming interface for Super Video Graphics Array (SVGA) displays, called the VESA BIOS Extension. Typically, an SVGA display can support a palette of up to 16,000,000 colors, although the amount of video memory in a particular computer may limit the actual number of displayed colors to something less than that. Image-resolution specifications vary. In general, the larger the diagonal screen measure of an SVGA monitor, the more pixels it can display horizontally and vertically.

Recently, new specifications have arisen. These include Super Extended Graphics Array (SXGA) and Ultra Extended Graphics Array (UXGA). The SXGA specification is generally used in reference to screens with 1280 x 1024 resolution; UXGA refers to a resolution of 1600 by 1200. Nowadays, the older specifications (VGA and SVGA) are often used simply in reference to their typical resolution capabilities. The table shows display modes and the resolution levels (in pixels horizontally by pixels vertically) most commonly associated with each.

Source:SearchNetworking.com