Series.PictureType (PowerPoint)

Returns or sets a value that specifies how pictures are displayed on a column or bar picture chart. Possible return values are xlStack - The picture is sized to repeat a maximum of 15 times in the longest stacked bar, xlStackScale - The picture is sized to a specified number of units and repeated the length of the bar, xlStretch - The picture is stretched the full length of the stacked bar.

ActivePresentation.Slides(1).Shapes(1).Chart.FullSeriesCollection(1).PictureType = xlStack