Splogs hotlinking my images

Suddenly, a whole bunch of very shady splogs decided to hotlink photos from one of my sites. Good news, Google still links to my site when showing these images. Bing and Yahoo… mixed bag. Duckduckgo too. Here's an htaccess contraption I devised to prevent that (I'm not worried about bandwidth):

# hotlinking RewriteEngine on RewriteCond %{HTTP_REFERER} !^$ RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?mywebsite.com [NC] RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?google.com [NC] RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?bing.com [NC] RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?yahoo.com [NC] RewriteCond %{HTTP_REFERER} !^http(s)?://(www\.)?duckduckgo.com [NC] RewriteRule \.(jpg|jpeg|png|gif|svg|jp2|jpx|webp|jxr)$ //hotlinking.png [NC,R,L] 

…any thoughts?