Cocoa OSX：如何使图像可拖动

I have a panel with an image on it, and I want to make it so that you can copy a file (not the image,the image is only going to server as an icon for the file) into a folder by “dragging” the image outside of the application and into any other application that accepts files being dragged into it (ex. Finder). How can I do this?I have a panel with an image on it, and I want