how to making a page load itself into a new popup window ???

i do 1 project with JAVA _ Desktop Ajax but i have one problem when insert image in Admin control pannel --> see bellow I have a main window where a user fills in a form.... When a user clicks on attach a picture it opens up in a pop up window.... Now what i want it to do is let the user attach a picture and when they click on insert and in main window will display image attached