Format related procedures in class PictureFormat (PowerPoint VBA)
Returns or sets the type of color transformation applied to the specified picture or OLE object.
The value of the ColorType property can be one of these MsoPictureColorType constants.
ActivePresentation.Slides(1).Shapes(1).PictureFormat.ColorType = msoPictureMixed
Returns or sets the transparent color for the specified picture as a red-green-blue (RGB) value.
For this property to take effect, the TransparentBackground property must be set to True. This property applies to bitmaps only. If you want to be able to see through the transparent parts of the picture all the way to the objects behind the picture, you must set the Visible property of the picture's FillFormat object to False. If your picture has a transparent color and the Visible property of the picture's FillFormat object is set to True, the picture's fill will be visible through the transparent color, but objects behind the picture will be obscured.
ActivePresentation.Slides(1).Shapes(1).PictureFormat.TransparencyColor = RGB(0,0,255)'blue