Again, just banking on not having run into such, but would there be use in a tag where other images in a Pixiv "manga" (where the Source link leads to a page of multiple images) have not been uploaded, for whatever reasons (in case of post #1298173 (NSFW), too many variations)? It's not always obvious that there's more to be seen, but that this extraneous content may not always be apt for Danbooru's catalogue.