The iPod nano Generation 2 was available in 2 GB, 4 GB, or 8 GB flash memory capacities, capable of supporting either 500, 1000, or 2000 songs. In addition to songs, it could hold up to 25,000 photos on its 1.5 inch (diagonal) LCD display.
The 2 GB model was only available in silver; the 4 GB model was available in silver, green, blue, and pink; and the 8 GB model was only available in black.
Source: EveryMac.com