Thanks @reslus for bring up this point.
The functionality already exists, just add this parameter in your shortcode:
[reviews_rating icon="/wp-content/uploads/your-business-logo.png"]
Accepted values are:
Positive (Google’s icon): yes, true, 1, show
Negative (Hide): no, false, 0, hide
Custom (Your choice): some-url/some-image.png (accepted extensions: jpg, jpeg, gif, svg)
At the moment, you can only set the icon for the shortcode and not the widget. I am planning add new functionality for the widget and Media library selection in coming versions.
