Resize picture to fit merged cell

try this

Sub ResizePic()
Dim r As Range, lTop As Long, lLeft As Long, lHeight As Long, lWidth As Long, shp As Shape
On Error Resume Next: Err.Clear
Set r = Application.InputBox("Click in the cell to hold the picture", Type:=8)
If Err Then Exit Sub

With r.MergeArea
    lTop = .Top
    lLeft = .Left
    lHeight = .Height
    lWidth = .Width
End With

For Each shp In ActiveSheet.Shapes
    If Not Intersect(shp.TopLeftCell, r.MergeArea) Is Nothing Then
        With shp
            .LockAspectRatio = msoFalse
            .Top = lTop
            .Left = lLeft
            .Height = lHeight
            .Width = lWidth
        End With
    End If
Next shp

End Sub

edited
oops, I did not read 'from anywhere on the worksheet'