VBA Code For Excel ..........................

Dear Expert,

Below written VBA code is being used by me to insert jpg picture in the excel file against the code number and its working very well and i need to incorpotate a small thing is if the picture is not available in the cell for the code it should write (Picture is not available) presently it is swhoing Blank .
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Sub ProcessFiles()
Dim sPath As String, s As String, r As Range
Dim shp As ShapeRange
Dim c As Range, cell As Range, sname As String
Dim p As Picture, diffwidth As Double, diffHeight As Double
sPath = "D:\2010I\Excel Pic\Complete Range _2010I"
If Right(sPath, 1) <> "\" Then sPath = sPath & "\"
Set r = Range("B2", Cells(Rows.Count, 2).End(xlUp))
For Each cell In r
cell.Offset(0, 1).Select
Set c = cell.Offset(0, -1)
s = sPath & cell.Value & ".jpg" 'remove the .jpg if the cell contains the extension
sname = Dir(s)
If sname <> "" Then
Set p = ActiveSheet.Pictures.Insert(s)
Set shp = p.ShapeRange
diffwidth = c.Width - p.Width
If diffwidth > 0 Then
p.Left = c.Left + 0.5 * diffwidth
Else
p.Left = c.Left
End If

diffHeight = c.Height - p.Height
If diffHeight > 0 Then
p.Top = c.Top + 0.5 * diffHeight
Else
p.Top = c.Top
End If
End If
Next

End Sub

Please help
Rgds Santosh