You use collections to organize folders in Picasa. Think of a collection as a master foldera container of other folders that share something in common, such as all family photos or pictures downloaded from the Web, for example. Unlike the folders in the Folder List (which represent actual directories on your hard disks), a collection exists only in Picasa.
When you run Picasa for the first time, it automatically creates two collections: Folders on Disk and Other Stuff. Picasa puts all folders that contain large images into the Folders on Disk collection; folders with smaller files are placed in the Other Stuff collection. Certain actions automatically create additional collections. For example, receiving files from Hello (Chapter 10) creates a From Hello collection, exporting images to a folder (Chapter 9) creates an Exported Pictures collection, and defining your first label creates a Labels collection.
Create collections. You can also create your own collections to organize folders.
The new collection appears in the Folder List, alphabetized by its name.
Move a folder to a different collection. Each folder can be in only one collection. To make folders as easy as possible for you to find, it's important that every one be in the most appropriate collection. You may want to reclassify some of the folders that were assigned to the Folders on Disk and Other Stuff collections, for example. You'll also want to do some reorganizing when you create new collections or add folders to the Picture Library.
In the Folder List, right-click the folder you want to move.
Rename a collection. While the names of automatically generated collections can't be changed, you can freely rename any collection you've created.
Right-click the collection name in the Folder List, and choose Rename Collection from the pop-up menu that appears.
Edit the name in the Rename Collection dialog box, and then click OK.
Password-protect a collection. You can assign a password to a collection to prevent others from seeing the folders and images within it. Whenever someone tries to view the collection by opening it in the Folder List, a Password Entry dialog box is presented.
Right-click the collection name in the Folder List. Choose Add/Change a password from the pop-up menu that appears (see previous page).
Collapsing the collection in the Folder List protects it. To do so, click the triangle button beside the collection's name. The next time you want to view the collection, click the triangle button again and supply the requested password.
To change a password, open the protected collection by supplying the current password. Right-click the collection name in the Folder List, and then choose Add/Change a password. Enter the new password and confirm it (see Step 2).
To remove password protection from a collection, open the protected collection by supplying the password. Then right-click the collection name in the Folder List, and choose Add/Change a password. Instead of entering a password, leave the dialog box blank and press (or click OK).
Remove a collection. You can eliminate collections that are no longer needed. Right-click the collection name in the Folder List, and choose Remove Collection from the pop-up menu that appears (see previous page). Click Yes in the Confirm dialog box. Any folders contained within the removed collection are moved to the Other Stuff collection. You can move those folders to a different collection by following the instructions on the previous page.