In a blog post: Microsoft stated:

A lot of players take screenshots of their captured Pokémon to show off to their friends—both digitally and in person. We had to make it easier for you to find all your Pokémon screenshots, so we went to work and partnered with Microsoft Research to bring a Pokémon detector to OneDrive. When you have the OneDrive app on your phone and camera upload is turned on, the screenshots you take from the game are automatically saved to OneDrive and 150 Pokémon are identified for your searching and viewing pleasure. You can also search for your favorite Pokémon by name.