Using PP2016, I have a macro that exports images as png files but the quality is much poorer than if I save each image individually - I tried various parameters but they didn't seem to make any difference. I notice that individually-saved images have a bit depth of 32 while the vba ones' is only 24. Assuming that the greater bit depth will improve the quality of the image is there a way to make the images export with a bit depth of 32? I wonder why the different method of saving results in different bit depths.

My current code is below.

Sub SaveImages()
Dim oPresentation As Presentation
Dim oSlide As Slide
Dim oShape As Shape
Dim sFilename As String
Dim sPath As String
Dim sli As Integer
Dim shi As Integer


Set oPresentation = ActivePresentation

For Each oSlide In oPresentation.Slides
sli = oSlide.SlideNumber
For Each oShape In oSlide.Shapes
If oShape.Type = msoGroup Then
shi = oShape.Id

sFilename = sli & "-" & shi & ".png"
sPath = "C:\Users\User\Pictures\pp" & sFilename
Call oShape.Export(sPath, ppSaveAsPNG)
End If
Next
Next
End Sub