Photoshop CS4 crashes in Save for Web and Devices or Lighting Effects, or when you use Camera Raw images.
Update to Mac OS X version 10.5.8.
The 10.5.8 update is located here, depending on the version of Mac OS you currently have installed:
Please contact Apple for further information about updating Mac OS.
Due to the nature of this issue, crashes can occur unexpectedly in other features as well. Adobe recommends you update to Mac OS X version 10.5.8.