needed to remove image extension using htaccess

needed to remove image extension using htaccess

I need to change or redirect the "example.com/photos/logo.jpg" to
"example.com/photos/logo" when user comes from google image search.
Therefore I've used RewriteCond %{REQUEST_URI}
photos/.*.(gif|jpg|jpeg|png)$ [NC] RewriteCond %{HTTP_REFERER}
^http://www.google.[a-z]{2,4}(.[a-z]{2,4})?/url\?.*$ [NC,OR] RewriteCond
%{HTTP_REFERER} ^http://www.bing.com/images/search?q=\?.*$ [NC,OR]
RewriteCond %{HTTP_REFERER} !^http://example.com/.*$ [NC] RewriteCond
%{HTTP_USER_AGENT} !(.bot.|slurp) [NC] RewriteRule ^gallery/(.*) /$1
[L,R=301]
Thank you.