Thanks for continuing to look into this. I admittedly have not heard the conversation you are referring to and I am uncertain what that conclusion was based on, but I am unable to support the assessment that this is happening because our system is resizing the images placed in the Optional eBay Gallery Images section upon submission to eBay at this point.
However, I have done some additional testing with respect to this situation over the course of this week and my results have matched what you reported precisely. In each test listing posted through Auctiva, the “zoom” feature has shown up when using only one gallery image and has failed to show up when using multiple gallery images.
I then posted a listing through the eBay Sell your Item form by placing the URL's of the exact same Auctiva hosted images from my previous test in the “Copy Web Files” section and the “zoom” feature showed up even when using multiple images.
We have passed this information along to eBay's technical team and we are hoping that they will be able to determine why this is occurring and, while I'm not in a position to make any promises as to what the results will be, I will report back here with any new information I am able to uncover about this.