I'm confused, you want to remove bad images that you're hosting on your own site?
I assume you actually want to push down bad images that are on other sites, that would make more sense. In that case, you'll need to know where and how to publish images on sites that will rank well naturally. Then you'll need to know how to push those up to suppress the negative images down to where you're happy with the results. If you've never done it before, it's not a simple process.