To change the icon on the existing Browser Node, you need to create a standard Microsoft Windows IPictureDisp referencing an image(.bmp/.gif/.jpg) file, then add the IPictureDisp to the client node resource and apply this new client node resource to Client Browser Node Definition object.
The following sample code requires reference to stdole type library and Microsoft.VisualBasic.Compatibility assembly.
Sub modifyIcon()
Dim oDoc As Inventor.Document
oDoc = m_inventorApplication.ActiveDocument
' Find the specified Browser Pane
Dim oPane As Inventor.BrowserPane
oPane = oDoc.BrowserPanes.Item("NewPane")
Dim oNode As BrowserNode
oNode = oPane.TopNode
Dim oDef As ClientBrowserNodeDefinition
oDef = oNode.BrowserNodeDefinition
' Create a standard Microsoft Windows IPictureDisp
' load image
Dim bmp As System.Drawing.Bitmap = _
New System.Drawing.Bitmap("c:\temp\a.bmp")
Dim resourcePic As IPictureDisp
resourcePic = Microsoft.VisualBasic. _
Compatibility.VB6.ImageToIPictureDisp(bmp)
' Create new Client Node Resource
Dim oRsc As Inventor.ClientNodeResource
oRsc = oDoc.BrowserPanes.ClientNodeResources. _
Add("MyRsc", 2, resourcePic)
' Change the icon
oDef.Icon = oRsc
End Sub