Pokemon photos are widely available and can easily be found online, such as on websites dedicated to the video game series, for example, Pokemon Database. The Pokemon Database website features pictures of 720 different species of Pokemon that were introduced up to Generation VI of the Pokemon video game series.
The first generation of Pokemon video games started with 151 different species of Pokemon, when the game was first launched in the United States in 1998. The number of Pokemon gradually increased, as new species are constantly introduced as newer versions of video games are released.
An in-game device, called a Pokedex, is used in the games to keep track of the Pokemon species that are encountered and/or captured by the player. Each Pokemon is designated a Dex number that starts with the Pokemon Bulbasaur at #001 to the sixth generation entrant, Volcanion at #721. Pokemon species are also categorized according to their type, which are usually Fire, Grass and Water for game starter Pokemon, and Electric, Ground, Flying, Psychic, Dragon, Ghost, Fairy, Ice, Rock, Steel, Dark, Bug, Poison and Normal Pokemon species.
When collecting photos of Pokemon species, it is worth noting that there are differences in the appearance of male and female Pokemon species. Such differences may be subtle, such as a fewer number of teeth, to more obvious differences, such as the Pokemon's coloration.