Image URL

Using the last ver of W3 total cache plugin.
This is the url of image in my site
http://wp.be-st.ru/wp-content/uploads/2013/05/large-3-636x310.jpg?56ad5e
After every image url ?56ad5e is added. How can I fix it?

http://wordpress.org/extend/plugins/w3-total-cache/
Without W3 pluging links are OK