IconButton not showing specified size of the icon

[zaj]

Hello there,

I am using SMARTGWT version - SmartClient Version: v10.0p_2015-01-23/PowerEdition Deployment (built 2015-01-23).
I am trying to use an IconButton in a RibbonBar and I have an image of size 48x48 png. I set this icon on an IconButton but for some reason it is not scaling to the specified size. below is my code and I have also attached a screenshot of the RibbonBar where i am using the icon.

private IconButton getIconButton(String title, String iconName, boolean vertical)
	{
		IconButton button = new IconButton(title);
		button.setTitle(title);
		button.setAutoFit(false);
		button.setWidth(120);
		button.setIcon(iconName + ".png");
		button.setLargeIconSize(48);
		return button;
	}