Rectangle to Image (or Button)?

Are you asking how to create an iconimage control in a dialog?

createDialog = function ( ) {
   var dlg = new Window( 'dialog', 'Iconbutton Example Script' );
   var i = ScriptUI.newImage( new File('/c/t.png'), undefined, undefined, new File('/c/k.png') );// also accepts jpg
   dlg.iBtn = dlg.add ('iconbutton' , undefined,  i);
   dlg.btnPnl = dlg.add( 'panel', undefined );
   dlg.btnPnl.orientation = "row";
   dlg.btnPnl.alignment = "right";
   dlg.btnPnl.preferredSize [ 80, 80 ]
   dlg.btnPnl.okBtn = dlg.btnPnl.add( 'button', undefined, 'Ok', { name:'ok' });
   dlg.btnPnl.cancelBtn = dlg.btnPnl.add( 'button', undefined, 'Cancel', { name:'cancel' });
   return dlg;
};
initializeDialog = function( w ) {
   // Set up initial control states
     w.iBtn.onClick = function(){
          alert('Iconbutton pressed');
     }
    with ( w.btnPnl ) {
         // The Ok and Cancel buttons close this dialog
         okBtn.onClick = function ( ) { this.parent.parent.close( 1 ); };
         cancelBtn.onClick = function ( ) { this.parent.parent.close( 2 ); };
      }   
 }

runDialog = function( w ) {
   return w.show( );
};
var win = createDialog();
initializeDialog(win);
runDialog(win)