Changing media links once page is live

We currently have a live “website” using wordpress https://www.rosiesyarncellar.com. I am currently creating a new website with wordpress to replace the current site it is located at https://www.test.rosiesyarncellar.com/. When I upload any media- photos or pdf’s for use on this new site, they are tied to the test url. What happens when I change the URL of the site to https://www.rosiesyarncellar.com to replace the existing site? Does that make sense?