1. An image (original-site.com/rose.jpg) on the page (original-site.com/my-pics.html) will be indexed in Google Image Search.
2. A hotlinker will then create an inline link to this image (original-site.com/rose.jpg) on a page on his or her site (hotlinker-site.com/stolen-pics.html). Google will then reindex this same image as also belonging to the hotlinker page, and when you click on it in the image search results, it takes you to the hotlinker's page.
If the same image (same url and everything) is already indexed as belonging to a page (especially when that page domain is the same as that of the image), then Google should not reindex that image for a second time later, especially when the image domain is different from that of the hotlinker page domain