If you can't find exactly what you want in all the media files you have stored on your computer, and you're connected to the internet, there's an easy solution: Search Microsoft Office Online. This is a great Web site with loads of clips, and new clips are featured every day.
On the Clip Art and Media home page you can search for clips using keywords, just as you did in the task pane. Once you have found the ones you want, select them using the check box, and when you're ready, download them.
Clip Organizer will open once the clips are downloaded, so you can move them to other collections if you desire. The clips will appear in the Downloaded Clips folder and, depending on the keywords, will also be found in your existing collections. The clips will actually be stored by default in the My Pictures\Microsoft Clip Organizer folder, but you can choose to save them elsewhere.
The clips available through Microsoft Office Online are also available through Web Collections. You have to be online to see the clips, but while online you can select a clip, right-click, and choose Make Available Offline to save the clip to your hard drive. The choice is yours on using the Web site or the Web Collection—you'll have a bit more room to browse on the Web site, but using the Collection means you don't have to surf the Internet.