Hello, Bruce.
If you've created the new backup to the external drive, but you aren't able to select the old backup set from within the restore function, I recommend that you contact support as this should work.
How to reach support (FAQ) - http://forums.microsoft.com/WindowsOneCare/ShowPost.aspx?PostID=2421771&SiteID=2
Alternatively, your photos are in the zip files in the old backup set, but I'd not want to extract them manually.
-steve