tlrowley and wilsondm2:
Are you using Macs? My guess is that it's trying to display the resource fork file as an actual image.
When OS X writes to a FAT32 drive (like the Kindle), it creates the file (e.g. image.jpg), and an AppleDouble Macintosh file with the same name, prefixed with "._" (e.g. ._image.jpg). The leading dot causes it to be hidden.
If you can remove those files, I would guess you'll stop seeing the blank images.