Account assets folder paths are inconsistent

I'm using Windows XP and Balsamiq Mockups for Desktop 1.6.47.

When I manually copy an image into the account assets folder, two files with the same name show up in the image properties window. The first works and saves into the BMML as %24ACCOUNT/assets/filename.ext, which is different from the format originally discussed on the blog. The second does not work (the image freezes at "Loading 0%" and saves into the BMML file as %24ACCOUNT/filename.ext.