Just FYI, as this might be of use to others regarding the X-Cart Ebay Integration module:
On our site, we run NGINX and redirect all unsecure http traffic to secure https. This includes image files too. The problem is, Ebay for some odd reason, does not accept any image files over https. So when attempting to upload a product to Ebay, Ebay spits back an error.
I'm attempting to find a way now to tell NGINX to serve static image files (.jpg, .png, etc) via both http and https. That would solve this problem. If anyone has any tips or hints, please let me know!