CD Session Burner is a shareware data CD/DVD burning application for MacOS X. Via a simple drag and drop interface you can create any number of volumes on a single CD-R adding more until the disk is actually full.
Select images from your iPhoto 6 library to burn to a CD Session or a DVD. Backup all your photos taken since a specific date, by film roll or select albums that you've created in iPhoto to be burned to disk.
Disk Burner, that is built into Mac OS X, burns an entire disk at once whether you have used all the space on it or not. CD Session Burner lets you burn as many smaller volumes to the disk as you like until the space is all used up. That makes it perfect for doing incremental backups as you work on projects. When you use a multi session disk each session will mount as a separate volume.