How to include a dynamically created file in the project?

How to include a dynamically created file in the project?

I have dynamically created a text file in my project location using
string path = Server.MapPath("~") + "\\Images\\abc.png";
FileStream fs = File.Open(path, FileMode.OpenOrCreate);
But am unable to read that file as it is found to be not included in the
project. Including manually is the only way? How can we achieve this
dynamically?