Hi there,
In the current situation there is a big image which shows small:
The version of the theme you are using is very old and we will not be able to give you proper support for that of an old codebase. You will need to backup your website completely and update the theme to version 5.2.5 and Cornerstone to 2.1.7.
In the version 5+ the thumbnail sizes uses the settings that you add in X > Launch > Options > Layout and Design and crop them accordingly.
Thank you.