PhotoRescue is a tool that I highly recommend. You will be able to extract files when corruption occurs, and also retrieve files that you have accidentally deleted. The free trial version allows you to view thumbnails of the images it is able to recover. The registered version ($29) will allow you to save the images that PhotoRescue can recover.

For more details, see the article "Recovering Lost Images" in Volume 3, Number 2 of The Digital Image for 2003. This article includes a discussion of how corruption occurs, how to avoid it, and what to do when images are lost.

Download the latest free demo version for Windows and MacOS from DataRescue.