I was having this same problem too. A search of the Apple Discussions board gave a pretty useful solution. Use Image Capture, Click on "Download Some...", and then select them all and go to Edit -> Delete. Seems to have worked for me.
Here's the link to the Discussion that I found this solution to. (Note, it does require a Mac.)
http://discussions.apple.com/message.jspa?messageID=5781213
Hope that helps for the future.