Noooooo! Not that!
No, this is even better – the satisfaction that comes with dealing with bandwidth leechers. These are the people who hotlink images from your site to their pages; mostly those who have avatars on bulletin boards and the like. Now, you can simply deny these people your images, saving you on bandwidth.
Of course, you could substitute the image the person’s posted for something rude – this doesn’t save your bandwidth (much) – but of course, this should be reserved for special people, especially right-wing cuntish kids in the USA who use you as examples of “homos what should be kiled” (sic).
So, two examples for all you apache & mod_rewrite users:
This will simply deny hotlinkers access to your images:

# Logging
RewriteLog /var/log/apache/rewrite.log
RewriteLogLevel 1
# Deny hotlinking
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !www\.yoursite\.com [NC]
RewriteCond %{HTTP_REFERER} !google\. [NC]
RewriteCond %{HTTP_REFERER} !search\?q=cache [NC]
RewriteRule .*\.(gif|GIF|jpg|JPG|bmp|BMP|png|PNG)$ – [F]

Remember to change yoursite to the URL of your own site, and the path to your log if you want to use that.
If you’re desired to change the image to something rude, do this:

# Fuck off little shit
RewriteCond %{HTTP_REFERER} myspace\.com [NC]
RewriteRule .*\.(gif|GIF|jpg|JPG|bmp|BMP|png|PNG)$ http://www.mysite.com/cunt.gif [R,L]