The source code

    Ext.onReady(function(){
        var chooser, btn;

        function insertImage(data){
        	Ext.DomHelper.append('images', {
        		tag: 'img', src: data.url, style:'margin:10px;visibility:hidden;'
        	}, true).show(true).frame();
        	btn.focus();
        };

        function choose(btn){
        	if(!chooser){
        		chooser = new ImageChooser({
        			url:'get-images.php',
        			width:515,
        			height:350
        		});
        	}
        	chooser.show(btn.getEl(), insertImage);
        };

        btn = new Ext.Button({
    	    text: "Insert Image",
    		handler: choose,
            renderTo: 'buttons'
        });
    });