What does that even mean? The image was uploaded on the website into the og:image tag (easy to do), and Twitter updated it into a post that was made prior to the image upload at the website. People can twist this into something much more complicated than it is, but it's done all the time. Just Twat something out and include a link to some website. It'll include a snippet about that website with an image. The image can either be something random that Twitter pulls OR it'll be whatever is set in the og:image tag. Not all sites have the og:image tag set, so in that case, it'll probably pull the first image it finds on the home page.