Where do I put the .htaccess if I want to prevent bandwidth stealing?

[Gutspiller]

Do I put the .htaccess in my forum directory if I want it to display a different image when people try and link to my attachments?

Also, I was told something like this would work at replacing attachments with my own image:

RewriteEngine on
RewriteCond %{HTTP_REFERER} !^$
RewriteCond %{HTTP_REFERER} !^http://3dnewz.com.*$ [NC]
RewriteCond %{HTTP_REFERER} !^http://www.3dnewz.com.*$ [NC]
RewriteRule .*\.(gif|GIF|jpg|JPG|mpg|MPG)$ http://www.3dnewz.com/images/banners/stealer.jpg

will that code work with forum attachments and would I just place the .htaccess file in my forum directory? Also, I heard that CuteFTP is unable to see .htaccess files already on the server. Does anybody know if this is true? I don't want to overwrite anything that needs to be there.

Thanks.