Website Menu isn't responsive, kindly help.

Hello there, thank you for helping me out earlier.

I have one small issue and i hope you people can help me out with that. Kindly go through the issue below.

My present website menu isn’t responsive, when the screen size is changed only the logo is being responsive and the menu images are not. I am using the plugin menu image to show the image instead of the menu title. Kindly suggest a CSS responsive code for this or kindly share a solution where i can show the menu as in the website with out the help of a plugin.

Screenshot Link: http://oi65.tinypic.com/a3iamh.jpg

Website URL : http://demo.inspiredtravels.in/

Would be eagerly waiting for your reply.
Thank You.