Export to Pdf: Image not shown

I'm a newbie with Crystal Report.

I'm trying to export a loaded Crystal report document in C# to pdf.

I have a image in the document but it will not show. The Image path is an url.

If I export it to CrystalReport format it works fine and the image is shown.

crdoc.ExportToDisk(ExportFormatType.CrystalReport, logPath + debugFileName + "_1.rpt");

If I export it to Pdf format it will not work.

crdoc.ExportToDisk(ExportFormatType.PortableDocFormat, logPath + debugFileName + ".pdf");

I also tried to export the document like this

ExportOptions crExportOptions = new ExportOptions();

DiskFileDestinationOptions crDiskFileDestinationOptions = new DiskFileDestinationOptions();

crDiskFileDestinationOptions.DiskFileName = logPath + debugFileName + "_2.pdf";

crExportOptions.DestinationOptions = crDiskFileDestinationOptions;

crExportOptions.ExportDestinationType = ExportDestinationType.DiskFile;

crExportOptions.ExportFormatType = ExportFormatType.PortableDocFormat;

crdoc.Export(crExportOptions);

The refrences i'm using is

CrystalDecisions.CrystalReports.Engine vers. 11.5.3700.0

CrystalDecisions.Enterprise.Framework vers. 11.5.3300.0

CrystalDecisions.Enterprise.InfoStore vers. 11.5.3300.0

CrystalDecisions.ReportSource vers. 11.5.3700.0

CrystalDecisions.Shared vers. 11.5.3700.0