debugging runtime error 1004

[JB Bates]

I have a workbook that contains 100 worksheets. On each work sheet I have
the following code (see below) that runs and when a particular person is
selected from a drop down list a jpg of their signature displays at the top
of each sheet.

This was working fine but I am now getting the following error after I
select a person from the drop down and then when ever i try to input data
into any other cell. The error message is:

Runtime Error '1004'" Unable to set the top property of the picture class

It then allows me to END or debug. if i select debug it opens the VBA
window to the code and highlights this line

oPic.Top = .Top

But i don't know what to to do with that line of code to debug

PLEASE HELP

thanks in advance - JB


Private Sub Worksheet_Calculate()
Dim oPic As Picture
Me.Pictures.Visible = False
With Range("ad1")
For Each oPic In Me.Pictures
If oPic.Name = .Text Then
oPic.Visible = True
oPic.Top = .Top
oPic.Left = .Left
Exit For
End If
Next oPic
End With
End Sub