You could start with this and play with it!
Sub fixPic()
Dim rayPic() As Shape
Dim osld As Slide
Dim opic As Shape
Dim L As Long
ReDim rayPic(1 To 1)
Set osld = ActiveWindow.Selection.SlideRange(1)
For Each opic In osld.Shapes
If isPIC(opic) Then
opic.Height = 100
Set rayPic(UBound(rayPic)) = opic
ReDim Preserve rayPic(1 To UBound(rayPic) + 1)
End If
Next opic
rayPic(1).Left = 10
rayPic(1).Top = 100
rayPic(1).Select
For L = 2 To UBound(rayPic) - 1
rayPic(L).Left = rayPic(L - 1).Width + rayPic(L - 1).Left + 10
rayPic(L).Top = 100
rayPic(L).Select False
Next L
With ActiveWindow.Selection.ShapeRange.Group
.LockAspectRatio = True
.Width = ActivePresentation.PageSetup.SlideWidth - 20
.Left = 10
.Ungroup
End With
End Sub
Function isPIC(opic As Shape) As Boolean
If opic.Type = msoPicture Then isPIC = True
If opic.Type = msoPlaceholder Then
If opic.PlaceholderFormat.ContainedType = msoPicture Then isPIC = True
End If
End Function