Dodgy Looking Backlinks

I'm confused about backlinks at the moment. So far I have two back links that are legitimate but 40odd that are clearly spam websites. I can't work out how to get rid of them and here's why: When I visit the backlinks they appear to be using images from my website to promote products they are selling, the backlinks are linking directly to my images so when you click on the images they open up in a tab with an address that's my website. The images that they're using aren't even on my website anymore. The other weird thing is that they are retail listings hidden in the back end of legitimate website, for example, one was an international college but the listing was using their URL and there is no click through link to get through to the listing. If that makes sense. So I have a few questions: 1)what on earth is going on here? 2)is this likely damaging my SEO score? 3)how do I get rid of them?