I've studied your applications written on codeproject
and discussed to my senior but he refuses to use it in a long way.
The thing is only to receive the images and show them without saving,,, its complete thing like you have done..
doesn't a modal need a user respose yes/no when you do a dlg.domodal that thread stops until the user responds
True, but if it's the main window there is no other thread to worry about. You can do lots of actions within the dialog box while it is on the screen. Maybe you should explain exactly what problem you are trying to solve, rather than deciding on the window type before you know what you want to do with it.