If you are are playing with Andrew's VSTO Tutorial  and are having with the image rendering you might have put your GetResourceBitmap function into your ImageConverterclass like i was doing issues (Thanks Kathleen McGrath for finding my mistake!!) i have pasted the completed code below

#Region "Usinng directives"

Imports System
Imports System.Collections.Generic
Imports System.Diagnostics
Imports System.Text
Imports System.Reflection
Imports System.Runtime.InteropServices
Imports System.Windows.Forms
Imports Office = Microsoft.Office.Core

#End Region

#Region "service request implementation"

Partial Public Class ThisApplication

 Protected Overrides Function RequestRibbonService() As Object
  Return New Ribbon1()
 End Function

End Class

#End Region

<ComVisible(True)> _
 Public Class Ribbon1
 Implements Office.IRibbonExtensibility

#Region "Fields"
 Private ribbon As Office.IRibbonUI
#End Region

#Region "Initialization"

 Public Sub New()
 End Sub

 Public Function GetCustomUI(ByVal ribbonID As String) As String Implements Office.IRibbonExtensibility.GetCustomUI
  Return GetResourceText("Ribbon1.xml")
 End Function

 Public Sub OnLoad(ByVal ribbonUI As Office.IRibbonUI)
  Me.ribbon = ribbonUI
 End Sub

#End Region

 Public Sub OnToggleButton(ByVal control As Office.IRibbonControl, ByVal isPressed As Boolean)
  If (isPressed) Then
   MessageBox.Show("Hello World!")
  Else
   MessageBox.Show("Released!")
  End If

    End Sub

    Public Shared Function GetResourceBitmap( _
    ByVal resourceName As String) As System.Drawing.Bitmap
        Dim asm As Assembly
        Dim resources As String()
        Dim image As System.Drawing.Bitmap

        asm = Assembly.GetExecutingAssembly()
        resources = asm.GetManifestResourceNames()
        image = Nothing

        For Each resource As String In resources
            If (resource.EndsWith(resourceName)) Then
                Dim stream As System.IO.Stream
                stream = asm.GetManifestResourceStream(resource)
                If (stream Is Nothing) Then
                    Exit For
                End If

                Dim extension As String
                extension = System.IO.Path.GetExtension(resourceName).ToLower()
                Select Case extension
                    Case ".ico"
                        image = New System.Drawing.Icon(stream).ToBitmap()
                    Case ".jpg"
                    Case ".bmp"
                    Case Else
                        image = New System.Drawing.Bitmap(stream)
                        image.MakeTransparent()
                End Select

                stream.Close()
                Exit For
            End If
        Next
        Return image
    End Function

    Public Function GetImage(ByVal control As Office.IRibbonControl) As stdole.IPictureDisp
        Dim pictureDisp As stdole.IPictureDisp
        pictureDisp = Nothing

        Select Case control.Id
            Case "toggleButton"
                pictureDisp = ImageConverter.Convert(GetResourceBitmap("blankcd.ico"))
        End Select
        Return pictureDisp
    End Function

#Region "Helpers"
 Public Shared Function GetResourceText(ByVal resourceName As String) As String
  Dim asm As Assembly = Assembly.GetExecutingAssembly()
  Dim resources As String() = asm.GetManifestResourceNames()
  For Each resource As String In resources
   If resource.EndsWith(resourceName) Then
    Dim resourceReader As System.IO.StreamReader
    resourceReader = New System.IO.StreamReader(asm.GetManifestResourceStream(resource))
    If Not resourceReader Is Nothing Then
     Return resourceReader.ReadToEnd()
    End If
   End If
  Next
  Return Nothing
 End Function
#End Region
End Class

Friend Class ImageConverter
    Inherits System.Windows.Forms.AxHost

    Sub New()
        MyBase.New(Nothing)
    End Sub

    Public Shared Function Convert(ByVal image As System.Drawing.Image) As stdole.IPictureDisp
        Return AxHost.GetIPictureDispFromPicture(image)
    End Function

End Class

Ribbon.xml

<customUI xmlns="http://schemas.microsoft.com/office/2006/01/customui" onLoad="OnLoad">
  <ribbon startFromScratch="false">
    <tabs>
      <tab id="VSTO.Tab" label="Hello From Chuck" visible="1">
        <group id="VSTO.Group" label="Hello Kathleen" visible="1">
          <toggleButton id="toggleButton" label="Icon Here Now"
               screentip="Hello World Tooltip" onAction="OnToggleButton"
               size="large" getImage="GetImage"/>

        </group>
      </tab>
    </tabs>
  </ribbon>
</customUI>