These are the minimum requirements for Leopard...
PowerPC G4 (867MHz or faster) processor
* 512MB of memory - MINIMUM
* DVD drive for installation
* 9GB of available disk space
* Some features require a compatible Internet service provider; fees may apply.
* Some features require Apple's .Mac service; fees apply.
Here are the requirements for iLife '08 (which included iPhoto)
* Mac computer with an Intel, PowerPC G5, or PowerPC G4 processor.
* iMovie requires a Mac with an Intel processor, a Power Mac G5 (dual 2.0GHz or faster), or an iMac G5 (1.9GHz or faster).
* iDVD requires a 733MHz or faster processor.
* 512MB of RAM; 1GB recommended. High-definition video requires at least 1GB of RAM.
* Mac OS X v10.4.9 or later.
* 3GB of available disk space.
* DVD drive required for installation.
* QuickTime 7.2 or later.
* Other configurations may be supported. AVCHD video and 24-bit recording have additional requirements. Visit iMovie ’08 Camcorder Support for more information on AVCHD.
* 24-bit recording in GarageBand ’08 requires a Mac OS X compatible audio interface with support for 24-bit audio. Please consult the owners manual or manufacturer directly for audio device specification and compatibility.
* Burning DVDs requires an Apple SuperDrive or compatible third-party DVD burner.
* iPhoto print services are available in the U.S., Canada, Japan, and select European countries. Internet access required; fees and terms apply.
* iWeb requires Internet and web server access (.Mac recommended).
* Some features in iLife require .Mac. The .Mac service is available to persons age 13 and older. Annual membership fee and Internet access required. Terms and conditions apply.
iLife '06 w/ iPhoto 6 (which is the previous version) might work better for you if you can get your hands on it -- esp. if you have Tiger...
Hope this helped!
Maggie B