The Diversity Visa (DV) program is congressionally-mandated and allows up to 55,000 persons from nations that are historically under-represented in terms of migration to the United States to qualify each year for immigrant visas.

The program is also known as the “green card lottery” or "dvlottery", because the winners are determined through a random drawing from among the 10–12 million people who enter each year.
 
The DVLottery program usually takes place at the end of each year, while winners are announced between April and June of the following year. A green card entitles the holder to live and work in the United States indefinitely and without restrictions.

New Rules: Digital Processing
Starting in 2003, the U.S. State Department has significantly changed the rules for this program. All applications should now be filed electronically. The requirements are very strict: Photos should be in JPEG format, either in color or grayscale; monochrome images (2-bit color depth) will not be accepted. A new digital photograph must have a resolution of 300 pixels wide by 300 pixels high, and a color depth of either 24-bit color, 8-bit color, or 8-bit grayscale. If an existing photo is scanned, it must have a resolution of 150 dots per inch (dpi). The original photo should be 2 x 2 inches in size. The same rules regarding the depth of color apply. The maximum image size accepted will be sixty-two thousand five hundred (62,500) bytes.
 
The official guidelines set forth by the U.S. government in Public 4446 notice may be found here. Please be advised that any minor error in the application procedure will result in your immediate disqualification without further notice.