Well, assuming the rest of your code is how it needs to be, then make it like this:
order allow,deny
allow from all
Options +FollowSymLinks
RewriteEngine on
RewriteCond %{HTTP_REFERER} !^http://(www\.)?marypussy.com.*$ [NC]
RewriteRule \.(jpe?g|gif|bmp|png)$ - [F,NC,L]
RewriteEngine on
RewriteCond %{HTTP_REFERER} .*fusker*.*$ [NC]
RewriteRule .*\.(gif|jpg|jpeg|bmp|png)$ - [F,NC]
ErrorDocument 400
http://www.marypussy.com/
ErrorDocument 403
http://www.marypussy.com/
ErrorDocument 404
http://www.marypussy.com/
ErrorDocument 500
http://www.marypussy.com/
ErrorDocument 501
http://www.marypussy.com/
ErrorDocument 503
http://www.marypussy.com/
The null referrer might be ok to block, but if you submit to places who use firewalls, and get rejected because of "broken images", thats likely why.
I also dont know why you'd need your
order allow,deny
allow from all
Since you are not denying from anything. But I'm no expert either.