Public Sub SetAsIconAndText()
                ' Make sure button is showing Icon And Text
                Dim pUID As New UID
                pUID.Value = "{F53B91E1-C520-41a7-941C-686AA071D1A2}"  ' Toolbar GUID
            Dim pCommandBar As ESRI.ArcGIS.Framework.ICommandBar
            pCommandBar = m_application.Document.CommandBars.Find(pUID, True, False)
            Dim i As Integer
            If Not pCommandBar Is Nothing Then
                For i = 0 To pCommandBar.Count - 1
                    If pCommandBar.Item(i).Name = "FocusCorp_FocusEllipse" Then ' use the Property NAME of the button
                        pCommandBar.Item(i).Style = esriCommandStyles.esriCommandStyleIconAndText
                        Exit For
                    End If
                Next
            End If
        End SubUIDClass p_UID = new UIDClass(); p_UID.Value = ThisAddIn.IDs.<ButtonID>; ICommandItem p_CommandItemLogin = ((IDocument)ArcMap.Document).CommandBars.Find(p_UID, false, true) as ICommandItem; p_CommandItemLogin.Style = ESRI.ArcGIS.SystemUI.esriCommandStyles.esriCommandStyleIconAndText; p_CommandItemLogin.Refresh();
base.m_bitmap = new Bitmap(GetType(), bitmapResourceName);
I found this:
http://gis.stackexchange.com/questions/1297/can-you-programmatically-change-the-button-image-for-a-e...
and it works for me! 😄
private void SetButtonStyle()
{
    ICommandBars commandBars = ArcMap.Application.Document.CommandBars;
    ICommandItem commandItem = commandBars.Find(ThisAddIn.IDs.YourButtonClassNameHere, true, false);
    if (commandItem != null)
    {
        commandItem.Style = esriCommandStyles.esriCommandStyleIconAndText;
    }
}
Public Sub SetAsIconAndText() ' Make sure button is showing Icon And Text ' Dim pUID As New UID 'not needed ' pUID.Value = My.ThisAddIn.AddInID ' ' Toolbar GUID ' not needed Dim pCommandItem As ESRI.ArcGIS.Framework.ICommandItem pCommandItem = My.ArcMap.Application.Document.CommandBars.Find(My.ThisAddIn.IDs.PrecisionXYButton, true, false) pCommandItem.Style = ESRI.ArcGIS.SystemUI.esriCommandStyles.esriCommandStyleIconAndText End Sub
    Public Sub SetAsIconAndText()
        ' Make sure button is showing Icon And Text
        Dim pUID As New UID
        pUID.Value = "{6298A204-AD3A-9573-D5E7-E8952250BA36}"  ' Toolbar GUID"
        Dim pCommandItem As ESRI.ArcGIS.Framework.ICommandItem
        pCommandItem = My.ArcMap.Application.Document.CommandBars.Find(pUID, True, False)
        pCommandItem.Style = ESRI.ArcGIS.SystemUI.esriCommandStyles.esriCommandStyleTextOnly
    End Sub
					
				
			
			
				
			
			
				
			
			
			
			
			
			
		
The code below works, but never found a way to have it work on loading the toolbar.
OnClick - well, thats too late
OnUpdate ?
Sub Finalize?
AddIns are not loaded at Application StartUp , Delay loading...