preventing access to images in 'mobile' folder
I've published a sample version of my course for the web with HTML5 output, but am concerned about having the images in the 'mobile' folder available to anyone who finds the directory.
Is there a way to allow access the course online, but prevent people from getting hold of these images, and from them being indexed by search engines? I'd rather not password-protect the directory, as that would be one more step between people seeing my sample course and purchasing the full version.
I know I can add the directory to a robots.txt file, but that can be an alert that there is potentially desirable content in the folder.
Does anyone have any suggestions on this?