Hide images url in HTML for eBay listing

I need to publish thousands of listing on eBay websites. For every item, I will have an HTML description. No Javascripts are allowed. No i-frame are allowed. I will have an excel file, where I will have the html description for every item. For every HTML description I will have from 1 to 5 image urls which I need to put into the HTML file. Images urls are hosted on an external server, whose I don't have access to the control panel. (but I do have plenty rights to access the images) What I need from the freelancer: I would like the images urls to be COMPLETELY HIDDEN from anyone who would like to check the images urls. I will generate new items and new HTML every day, so it must be a fixed solution, I mean, something that I can apply in every situation where I need to hide an url in any HTML. Please note: no jave-scripts are allowed, no i-frame. Images URLS will be https. The HTML must be complaint with all latest ebay requirements.