I run a wallpapers site, and want to restrict/disable the direct viewing/downloading of images... for example:

I want to disable that if a user type the image url for direct downloading like that: http://www.mysite.com/somedir/image.jpg he will get a permission error!

I only want to allow the download/viewing of the image within my pages like user clicks on a link wihin the pages to view/download the image!

I saw this example on a russion wallpaper site I thing this can be done through .htaccess...

Any help and idea appreciated