When you boot to your installer DVD, the first screen that you see is to choose a language. Continue past that screen. You will then see menus at the top of the next screen. You will find Disk Utility in the Utilities menu.
When you choose the Archive & Install option, you will see a sub-option to save your files and settings. If you choose that sub-option, then you should expect that the installation will save your old system in a new folder on your hard drive "Previous Systems", and that your documents, settings, and apps (including your photos) will be automtically transferred to the newly installed system. Usually finishes with no problems. However, the install process will occasionally kick out some errors, as any major install might. As always, you should assure that your present system and files are safe by completing a full back up of your hard drive before you begin the reinstall of your system.