Tradionally, under Linux, anti-image leeching routines are done using mod_rewrite and a .htaccess file.
Under the Zeus webserver, you can now do this using the rewrite.script feature on our Linux hosting packages. Below is an example of what to place in the rewrite.script file, which needs to be uploaded to your web directory.
Please note: lines beginning with a # are comments, and words in italics should be replaced with your domain name etc.
RULE_0_START:
# This is a list of image file extensions to check against
insensitive match URL into $ with \.(gif|jpg|jpeg|png)$
if not matched then goto RULE_0_END
# Check the incoming site referer value
set SCRATCH:COND = %{IN:Referer}
match SCRATCH:COND into % with ^$
if matched then goto RULE_0_END
# This site here is allowed to display images from your site
set SCRATCH:COND = %{IN:Referer}
insensitive match SCRATCH:COND into % with ^http(s)?://(www\.)? allowed.site1.com
if matched then goto RULE_0_END
# This site here is allowed to display images from your site
set SCRATCH:COND = %{IN:Referer}
insensitive match SCRATCH:COND into % with ^http(s)?://(www\.)?allowed.site2.com
if matched then goto RULE_0_END
# This image here is allowed to be displayed (your "do not leech" image)
set SCRATCH:COND = %{URL}
insensitive match SCRATCH:COND into % with ^/images/noleech.jpg
if matched then goto RULE_0_END
# This is the full url to your "do not leech" image
set URL = http://www.my-domain-name.com/images/noleech.jpg
set RESPONSE = 302
set OUT:Location = %{URL}
set BODY = Please try <a href="%{URL}">here</a> instead
goto END
RULE_0_END:
