主机流量经常超标怎么排查解决？

最近主机流量用的厉害，一天要用掉1-2G流量，咨询客服说是图片被盗链。然后我就搜索按照网上的更改.htaccess教程添加了图片防盗链代码。不过好像没用，现在仍然是一样。请问现在该怎么去排查、解决？

下面是代码：
RewriteEngine On
RewriteBase /wp-content/uploads/
RewriteCond %{HTTP_REFERER} !^$ [NC]
RewriteCond %{HTTP_REFERER} !mianfeib.com [NC]
RewriteCond %{HTTP_REFERER} !photozero.net [NC]
RewriteCond %{HTTP_REFERER} !zhuaxia.com [NC]
RewriteCond %{HTTP_REFERER} !xianguo.com [NC]
RewriteCond %{HTTP_REFERER} !google.com [NC]
RewriteCond %{HTTP_REFERER} !feedburner.com [NC]
RewriteCond %{HTTP_REFERER} !feedsky.com [NC]
RewriteCond %{HTTP_REFERER} !baidu.com [NC]
RewriteRule .*\.(gif|jpg|png|rar)$ 微博相册图片地址.jpg [L,NC,R]
# BEGIN WordPress
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ – [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
# END WordPress