Sub ExportMe()
    Dim ExportPath As String   ' drive:\path to export to
    Dim Pixwidth As Integer    '  size in pixels of exported image
    Dim Pixheight As Integer
    Dim oSlide As Slide

    ' Edit to suit
    Pixwidth = 1024    '  arbitrarily ... set whatever value you like here

    ' Set height proportional to slide height
    Pixheight = (Pixwidth * ActivePresentation.PageSetup.Slideheight) / ActivePresentation.PageSetup.Slidewidth

    ExportPath = ActivePresentation.Path & "\"

    Set oSlide = ActiveWindow.View.Slide
    With oSlide
        .Export ExportPath & "Slide" & CStr(.SlideIndex) & ".JPG", "JPG", Pixwidth, Pixheight
    End With

End Sub