Recover Deleted JPEGS?

I recently deleted approximately 400 high resolution JPEGS from my internal hard drive. Immediately realizing my error, I started Data Rescue II in an attempt to recover them. DRII found all of the files, and I had it copy them to my external drive. However, approximately 2/3 of the files appear to be incomplete (both based on file size, and when I load them in preview). Interestingly, all of the icon previews for each file show a complete image. How is this so?

I was just thinking back, and the folder I deleted also would have contained Canon RAW files (.cr2) to go with each picture. Unfortunately, DRII can't recognize these, I believe. Maybe they would still be intact?

Any other ideas for how I can recover these files?

Mac OS X frequently stores a thumbnail for the image in the resource fork of the file. That is probably what you are seeing. Some image programs can also do this the header information of the file itself. Again, and unfortunately for you, you do not need the whole file to be able to see the preview.