How does Picasa handle symbolic links?
Picasa follows symbolic links (symlinks) and scans the files / folders pointed to by the symbolic links. Symbolic links pointing to folders will show up as regular folders in Picasa. When Picasa scans both a folder and symlinks pointing to that folder, the folder will show up multiple times in Picasa. This can lead to confusing behavior. We strongly recommend removing the duplicate folders, since changes to one folder will affect its duplicates. To remove a duplicate folder, right click on the folder and choose “Remove from Picasa” from the pop-up menu. Likewise, the same picture can show up multiple times if there are symbolic links pointing to it. Again, this can lead to confusing behavior where changing one picture affects another. We recommend hiding the duplicate pictures in this case. To do so, right click on a picture and choose “Hide” from the pop-up menu.