Using .HTACCESS files can be a great help to protecting your site’s images and content as well as for SEO. Noah Hendrix has written an article covering 5 Practical Solutions using .HTACCESS.

Some of the things covered are:

• Hotlinking Prevention
• IP Address Blocking
• Error Redirection
• Redirection during site maintenance
• Hiding Directory Listings

If you are using Apache webserver, you need to make sure you have mod_rewrite enabled.

For more information: 5 Fun and Practical Htaccess Solutions