Objects(<object name or index>).PercentHeight = Value
Where Value is the scale percentage of the original picture's height.
The Object.PercentHeight property sets or returns the picture object's height as a percentage of the height of the original picture.For example, a value of 50 will reduce the picture object's height by 50%.If the Object.PreserveAspectRatio property is set to true, then both the width and height values will be modified to preserve the aspect ratio of the image.