Button with image and empty string in Revit API

I am creating a new tab with some stacked buttons in revit. I need to place a button without text such as the attached image:
.

I am using the following code:

RibbonPanel panelMenu6 = application.CreateRibbonPanel(tabName, panelNameMenu6);

//create large buttons
PushButtonData Button23 = new PushButtonData("Button 23", "Button 23", directoryName + @"\pyRevit.dll", "pyRevit.TheCommand");
PushButton button23 = panelMenu6.AddItem(Button23) as PushButton;
button23.LargeImage = new BitmapImage(new Uri(directoryName + "\\Icons Resources\\Button 17 -bulleted-list-16 (2).png"));

//create small buttons
PushButtonData Button24 = new PushButtonData("Button 24", "Button 24", directoryName + @"\pyRevit.dll", "pyRevit.TheCommand");
Button24.Image = new BitmapImage(new Uri(directoryName + "\\Icons Resources\\Button 23 -address-16 (2).png"));

PushButtonData Button25 = new PushButtonData("Button 25", "Button 25", directoryName + @"\pyRevit.dll", "pyRevit.TheCommand");
Button25.Image = new BitmapImage(new Uri(directoryName + "\\Icons Resources\\Button 24 -paint-palette-16 (2).png"));
panelMenu6.AddStackedItems(Button24, Button25);

I tried to send an empty string instead of "button 25" but I receive an exception "The value cannot be empty. Parameter name: text".

That's the code when I receive the error. For instance, Button 24 without text:

PushButtonData Button24 = new PushButtonData("Button 24", **""**, directoryName + @"\pyRevit.dll", "pyRevit.TheCommand");

I try to create a pushbutton such as those in the attached pic 1. Image only and no text

Best practice would be to assign an appropriate name for the pushbutton. The Revit interface only displays like the image you sent when the Revit window has been resized smaller than allows for button names to appear.

Thanks to this blog I was able to create buttons without text. here is the code

using AW = Autodesk.Windows;
/// <summary>
    /// Each item shall be converted into Autodesk windows item
    /// </summary>
    /// <param name="tabName"></param>
    /// <param name="panelName"></param>
    /// <param name="itemName"></param>
    /// <returns></returns>
    public AW.RibbonItem GetButton(string tabName, string panelName, string itemName)
    {
        AW.RibbonControl ribbon = AW.ComponentManager.Ribbon;
        foreach (AW.RibbonTab tab in ribbon.Tabs)
        {
            if (tab.Name == tabName)
            {
                foreach (AW.RibbonPanel panel in tab.Panels)
                {
                    if (panel.Source.Title == panelName)
                    {
                        return panel.FindItem("CustomCtrl_%CustomCtrl_%"
                          + tabName + "%" + panelName + "%" + itemName,
                          true) as AW.RibbonItem;
                    }
                }
            }
        }
        return null;
    }
    /// <summary>
    /// A List contains items which shall be without text
    /// after converting each item to autodesk windows item using getbutton method
    /// set the text display to false
    /// and set the size to large
    /// </summary>
    /// <param name="ribbonItem"></param>
    /// <param name="tabName"></param>
    /// <param name="panelName"></param>
    public void editNoTextButtons(IList<RibbonItem> ribbonItem, string tabName, string panelName)
    {
        foreach (var item in ribbonItem)
        {
            var adwinbutton = GetButton(tabName, panelName, item.Name);
            adwinbutton.ShowText = false;
            adwinbutton.Size = Autodesk.Windows.RibbonItemSize.Large;

        }
    }

And that's how it looks like