Redirect raw .gif files to handler page via .htacces - my code doesn't work

问题

I have a viral image site where people can view funny gifs. A lot of people on reddit are sharing the raw .gif files however, rather than the page with .gif embedded. This is fine - but I'd like to redirect all people viewing raw image .gifs to a handler page called shareraw.php (located in root directory). This handler page will look exactly the same - just with a share link and button to check out the rest of the site.

Example of raw image location: http://gifsec.com/wp-content/uploads/GIF/2015/03/Scared-Reaction-Gif.gif

Share page location: http://gifsec.com/shareraw.php

Here is my code currently which is not working. When I go to a raw gif, nothing happens:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

Options +FollowSymLinks -MultiViews
RewriteEngine on

RewriteCond %{HTTP_REFERER} !^http://(www\.)?gifsec.com\.com/ [NC]
RewriteCond %{REQUEST_URI} /uploads/GIF/.*\.gif$ [NC]
RewriteRule ^(.*)$ /shareraw.php?img=$1 [R,L]


## EXPIRES CACHING ##
<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType image/jpg "access 1 year"
ExpiresByType image/jpeg "access 1 year"
ExpiresByType image/gif "access 1 year"
ExpiresByType image/png "access 1 year"
ExpiresByType text/css "access 1 month"
ExpiresByType text/html "access 1 month"
ExpiresByType application/pdf "access 1 month"
ExpiresByType text/x-javascript "access 1 month"
ExpiresByType application/x-shockwave-flash "access 1 month"
ExpiresByType image/x-icon "access 1 year"
ExpiresDefault "access 1 month"
</IfModule>
## EXPIRES CACHING ##