Filename of image in event box - c++

Question

I'm pretty new to GTK3.
I've created an array of EventBoxes and each of them contains an image. All boxes are linked to the same on_button_pressed method. When the user clicks an image, I'd like to get the file name of the image displayed in the event box. Is there any way this can be done?
Thanks for all the help.
---- EDIT 1 -------------------------
Code:
//In my header file, I've declared:
class Window : public Gtk::Window{
//....some other window elements....
Gtk::EventBox portraits[13];
Gtk::Image * portraitImage[13];
};
//In my .cc file, I've implemented:
Window::Window(){
//....creating some window elements ....
for(int i = 0; i < 13; i++){
portraitImage[i] = new Gtk::Image("empty.png");
portraits[i].signal_button_press_event().connect(sigc::mem_fun(*this,
&Window::doOnPortraitClicked));
portraits[i].set_image(*portraitImage[i]);
}
//..........some other code for displaying the window..........//
show_all_children()
}
//doOnPortraitClicked method
bool Window::doOnPortraitClicked(GdkEventButton * button){
?? GValue value = G_VALUE_INIT;
?? g_value_init (&value, G_TYPE_STRING);
?? g_object_get_property(G_OBJECT(button->get_image()), "file", &value);
?? string source = g_value_get_string(&value);
// How do I retrieve "empty.png" from the EventButton?
}
The question marks are lines I can't implement