title: Check if file exists in 2 directories, delete files that aren't in both directories
body: <p>So, I'm programming a game, but the compiler I use is written as a Windows batch file. I'm using Windows 10 as my operating system.
  In my game files, I have one folder with images, and another folder with upscaled versions of those images that have the same file name and extension.
  What I want to do is have the batch file go through all the images in the directory with the upscaled images, and check if a file with the same name and extension exists in the directory with the original images. If it doesn't exist in the original directory, it will delete it from the upscaled directory.</p>