Treeview images not appear in deep sub folders like above 13 level nodes

[M Kumar]

Hi,
    In treeview  from server side code we adding nodes and images in each node. like below in screenshot
http://prntscr.com/qcvcv3
    But when deep sub level folders like above 10,11,12,13 ....., image size will decrease and after 14 ,15 no more image appear, like below screenshot
http://prntscr.com/qcvdmn 
    What is the issue ?   my code is

 Private Sub ExploreTreeView(ByVal tnode As RadTreeNode)

                    Dim tempnode As New RadTreeNode(foldername, row("Database").ToString.Trim)
                    tempnode.CssClass = "GridCellSpace"
                    tempnode.ImageUrl = "images/Icons/DbFolder.png"
                    tempnode.Attributes("id") = Guid.NewGuid().ToString()
                    tnode.Nodes.Add(tempnode)

 End Sub

Inside rad panelbar item i added rad RadTreeView and i set width = 330 px and height = 400px
http://prntscr.com/qcvg6s

Pls reply asap
Thanks

[M Kumar]

Its ok fixed already