How to change image upload path to fix insecure content issues

I am experiencing mixed content warnings with my ssl certificate which is blocking the site on some servers. I read that all I have to do is take out http: from the upload path, but I cannot work out/find out how to do this.

It’s not something I can just change in settings, I’ve tried.

I am really desperate for help, I’m supposed to be going live today!!

Thanks in advance,
Michelle

http://www.clinlegal.com.au/clinlegalwp