PictureUnit Property
Returns or sets the unit for each picture on the chart if the PictureType property is set to xlScale (if not, this property is ignored). Read/write Long.
Example
This example sets series one in Chart1 to stack pictures and uses each picture to represent five units. The example should be run on a 2-D column chart with picture data markers.
With Charts("Chart1").SeriesCollection(1)
.PictureType = xlScale
.PictureUnit = 5
End With