Google announced today that it has acquired Picnik, a company that provides a fully-featured Web-based photo editing application. This is the latest in a recent string of acquisitions that has also seen Google snap up the social search site Aardvark.

Picnik is a flash-based photo editor capable of real-time cropping, resizing, rotating, special effects, and other manipulations. It can pull photos from websites including Picasa, Flickr, Facebook, and MySpace, or from a user's computer. The basic service is free, but the site offers a more sophisticated service for about $25 a year.

Google most likely wants to beef up its online photo-sharing service, Picasa, which currently has fairly minimal photo editing capabilities. It says it's not changing Picnik yet, but will be working on "integration and new features."

Other online photo editors include Photoshop.com, Aviary, and FotoFlexer.