how to add the the image md5 hash on the end of the background-image?

[phpjoe]

hi ,
I am sorry about my english.
I have a issue,when i add a image to my sprite,the spritesmith create the new css for me ,but the brower get the cache of the sprite image,so,I want to add a random to the of the image in the css,like "$brand-image: '../../images/order.sprite.png?v=20151022019'",but How can I do?
It is best to add the md5 hash string of the sprite image.

[twolfson]

This is a duplicate of #27 . Please see the example provided there.