# Creating and Testing the Image File

This chapter provides information about creating and testing the CD-ROM image file you will use to master your CD-ROM disc.

This chapter contains the following topics:

- Background and Overview
- Required Files and Folders
- Preparing Simple cdrom.image Files
- Preparing an Optimized CD-ROM Image
- Testing the CD-ROM Image File on a Macintosh
- Layout Tool Troubleshooting

NOTE: The procedure described in this document produces good results for most titles. The actual improvement in file access time and startup time caused by the optimized layout tool and the Catapult feature depends on the title. In addition, a custom layout done by the developer may be faster than an optimized layout done by the layout tool.