Have you tried to adjust the parameters in cOutpoutPage
• OutputPage(nPageNo, eDevice,nDeviceType, [, nleft, nTop, nWidth, nHeight, nClipLeft,nClipTop, nClipWidth, nClipHeight]) -

>oListener=CREATEOBJECT("ReportListener")
>oListener.ListenerType=3
>REPORT FORM MyReport PREVIEW OBJECT oListener
>cOutputFile = "c:\testreport(1).bmp"
>oListener.OutputPage(1, cOutputFile, 105, 0, 0, 768, 1024)
>
>It works but the header and footer images are not align like with report form preview or html output file (using htmllistener). The header and footer height & width are streched too short. How to avoid that?