PicasaMediaDetector.exe is Picasa an automated photo organizer. More information can be found here.

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A free software download from Google.

Picasa is software that helps you instantly find, edit and share all the pictures on your PC. Every time you open Picasa, it automatically locates all your pictures (even ones you forgot you had) and sorts them into visual albums organized by date with folder names you will recognize. You can drag and drop to arrange your albums and make labels to create new groups. Picasa makes sure your pictures are always organized.