Theme Options Page Update Logo

Hi All,

I’m a newbie to WordPress Development so bear with me.

Site: https://wordpress-portfolio-zacnespral21.c9.io/

On the site above I would like to add an option in the themes options page for the user to replace the brid logo(default) on the left hand side with whatever image they choose/upload. I was able to get the themes option page created and fill in some dummy content, but now im stuck. Currently the logo is being called via background-image on a span with the class of .portfolioLogo any help to get this working would be appreciated.

Thanks!