Google Picasa is an application that heklps to organize, archive and manage your photo collections. This app was pucrhased by Google in 2004 and developed by them since that year.
Is not a simple picture organizer, but also provides editing features, view images as slideshow, create photo collage, create movie presentation with custom audio tracks and different transitions.
Some popular editing functions that are included: crop, remove redeye, retouch, add text, change color temperature, shadows. Also includes powerful filters that will modify and improve your photo with one single click.
Other features includes geo tagging and social sharing.