What is causing the v=aaaaaaaaa redirection on images?

I would like to cache images and other static content elsewhere. However this is a pain to do when it’s already being messed with by suitecrm somehow. An example looks like this

http://192.168.1.102/themes/default/images/company_logo.png?v=5hn7lf_2rMOHFcJrKT2a7w

Is this a mod_rewrite function somewhere? I’d like images and other static files linked directly instead of redirecting to some php script. What’s the purpose of this?

Thanks!