Generally, we are getting the application path using Application.StartupPath. It will return the path of the executable file that started the application.
The Bin folder contains Release folder there I created a folder named images and save the icon image, So that we can access from the folder as we wish.
string imgpath = Path.Combine(Application.StartupPath, @"images\infi.ico");
NotifyIcon trayIcon = new NotifyIcon();
trayIcon.Icon = new Icon(imgpath);
Get the icon from the Image folder: