Load message when loading PNG

I'm trying to let the user know when a file with a PNG extension is used, it gives a notice about transparent PNGs, how do I give a message box when it loads a PNG?

var sPath = FileDialog.doFileDialog(true, "Select an Image File", oImageMgr.getImageOpenPath(), "Image Files(*.png *.jpg *.tif)");
if(sPath){
	oImage = new Image();

	if(oImageMgr.loadImage(sPath, oImage)){
		var oTexture = oImageMgr.getImage(sPath);
		var oFileInfo = new DzFileInfo(sPath);
		oImageMgr.setImageOpenPath(sPath);
		var sNodeName = "%1".arg(oFileInfo.baseName());
		
	if( DzFileInfo( String( "PNG" ))
	{ 
		MessageBox.information( "Your image is now PNG.", "Plane created!", "OK", "" );
	}