How can I extract image from a website into my rails project?

I am very new to Ruby on rails. I am making a web application in which I have to fetch RSS feeds from news websites, which I have done using gem feedzirra. I was thinking of extracting images from every feed url and posting it on my application. But I don't know which gem will be suitable for just extracting images from different websites. I thought of using nokogiri or opengraph but I don't know how to go about it. Can someone please guide me. Thank you I am very new to Ruby on rails. I am making a w