I have a root application and a "sub"-application in the /adm subfolder. The root application contains the images I want the public to view. I want the /adm to be able to access the /images folder in the root application to be able to add or delete files, as well as create/delete folders. How do we do access root/images from the /adm application?

As long as the directory resides on the server that houses your application, then you can access this by typing out the full path.
example sample: "c:\adm"