Regexp is one of those dark arts that no amount of googling can expose :-) Trust me. Yes, if you add that and don't forget:

RewriteCond %{HTTP_REFERER} !^http://mancheck.com/.*$ [NC]

You should be okay - unless there's another mancheck.com server like avs.mancheck.com etc. (there appear to be some out there!) So the + syntax might be smarter - if it works. You also have the first line

RewriteCond %{HTTP_REFERER} !^$

After re-reading what I copy-pasted from the internet before, I don't think it is necessary. It at best would allow sites with no referring URL to hotlink. I am trying out hotlinking without this line and seeing what happens. True, safer for the firewalled people...but I'd prefer safer for me :-) You pretty much have to take the .htaccess file one line at a time with regexps. Add a line, delete one, watch out for typos. And always check your logs to make sure you aren't inadvertently blocking legitimate use.

Almost forgot, Yes - XYCash is our program...one of the older gay programs out there.

-doug