If you want to create a short movie of several of your pictures with Picasa
then follow this procedure:
First regroup all the photos in a single album, more info on this FAQ
- Select your photo and click on Create> Movie
In the menu that opens select the Movie size and set the delay between pictures.
- Click on the OK button
- Select the Video compression options (if needed).
- Click on OK
- Picasa will render the movie.
- Once the process completed Picasa will open the folder containing your freshly created movie.