It appears that you contacted our Email Support reg the same concern and we responded back. We are copy/pasting our reply here for your reference:
'These encrypted URLs were allowed since you have added gstatic.com to your website whitelist. In most of Google products and services images are loaded from gstatic.com domain. Also note that these URLs are dynamically generated and will expire after some time.'
Mobicip Support Mar 22, 2016
Re: HOW TO BLOCK IMAGES FROM THIS SITE