Posted by Your images may fail to load or get replaced with random images when posting HTTPS links in Facebook.
Users have turned to Facebook’s Debugger tool to check the HTTPS links, and the results claim either the images in the URLs are corrupted, or the format is not supported. It’s been noted that URLs using HTTP seem to work just fine, but URLs using HTTPS do not.
https://marketingland.com/does-facebook-have-a-problem-with-https-urls-in-posts-with-images-265651