How to use different logo in the mini-site and affiliate login page?

The logo that you may upload in the merchant panel at Configuration > Design > Customize Logo (tab) > Logo and program name (section)  is the one that appears in all of the pages of Post Affiliate Pro. 
But what if someone wishes to use a different logo in the mini-site?

The solution is easy:
<img src="{$programLogo}" class="LogoImage">
  1. Upload your new (desired) logo image to your server, so that it is available online via some URL. 
  2. Create a new 'signup page' theme or modify your 'copy' of a default signup page theme  at Configuration > Design > Signup page theme. Simply click "Edit theme" on one of the default themes (or on your copy of a default theme) and the system will prompt you to name the new theme and afterwards the 'Theme editor' will show up.
  3. In the 'Theme editor' look up the following file: header.stpl
    and in that file find the following code:
  4. In that code replace the {$programLogo} variable with the URL leading to your logo image.
  5. Save your changes and when you exit the 'Theme editor'  click the "Set as default" button on the freshly created (modified) theme.