Picnik
Picnik makes photos fabulous with easy to use yet powerful editing tools. Adjust pictures to your needs, then get creative with various features. It's fast, easy, fun, and basic edition is free.
Picnik was acquired by Google in March 2010. Picnik is integrated with Picasa, Facebook, MySpace, Twitter, etc
Picnik is recommended for try out and you can see the details on the web site.
Picnik has quickly become the premier name in online image editing programs, offering dozens of tools to improve picture quality, countless filters and effects to stylize photographs and images while integrating seamlessly with many of the post popular photo-sharing and social networking sites on the Internet, including Facebook, MySpace, Flickr, Photobucket and others.
Picnik also includes a variety of textual and visual embellishments such as themed graphics to further personalize photographs and even provide scrapbook-like polishes.
Standout Features:
Creative page creation features, including photo collage and other scrapbook-style embellishments and themes
Extensions for major Internet browsers Firefox, Safari and Internet Explorer
Picnik API available on request to append additional tools and features or customize the user interface