Apple has just released an update for iLife which incorporates some fixes and security repairs.
Apple addresses several security vulnerabilities that existed in the imageIO framework.
Memory initialization has been corrected, and image validation improved, preventing application failure or arbitrary code execution when viewing TIFF images that contain malicious code.
Processing of TIFF images has also been changed to avoid a memory corruption problem that could cause similar problems.
The Update is for those NOT running 10.5.5 and is available via software update or on their site.