Depending on the quality of image you need and on whether a conversion of just the first page will do it for you, you could automate PowerPoint instead.
Set the PPT slide size to proportions that match the PDF
Insert the PDF as an object
Position it to 0,0 and set it to the slide's height and width
Save the slide as a PNG or GIF
Simple example, automated from within PPT
You could modify the code to automate PPT from other apps
Sub SavePDFAsPng(sPathToPDF As String, sPathToPNG As String)
Dim oPres As Presentation
Dim oSh As Shape
' Height/Width are hardcoded here
' You could get trickier and bring the PDF into any presentation
' once to get its proportions, delete it, set the slide size to the same
' proportions, then re-insert the PDF
Dim sngWidth As Single
Dim sngHeight As Single
sngWidth = 612
sngHeight = 792
Set oPres = Presentations.Add
With oPres
With .PageSetup ' set it to 8.5x11
.SlideHeight = sngHeight ' 11in * 72 points per inch
.SlideWidth = sngWidth
End With
.Slides.AddSlide 1, .SlideMaster.CustomLayouts(1)
With .Slides(1)
Set oSh = .Shapes.AddOLEObject(0, 0, sngWidth, sngHeight, , sPathToPDF)
Call .Export(sPathToPNG, "PNG")
End With
.Saved = True
.Close
End With
End Sub
Sub TestSavePDFAsPng()
Call SavePDFAsPng("C:\Temp\MyTest.pdf", "C:\Temp\MyTest.PNG")
End Sub