How to covert crystal report to bmp and send to response in web API using ASP.NET C#

var rd = new ReportDocument();
                    rd.Load(Path.Combine(System.Web.Hosting.HostingEnvironment.MapPath("~/Reports"), "Report.rpt"));
rd.SetDataSource(Rlist);
Stream stream = rd.ExportToStream(ExportFormatType.PortableDocFormat);
MemoryStream ms = new MemoryStream();
stream.CopyTo(ms);

public HttpResponseMessage Generate(MemoryStream ms)
       {
           var result = new HttpResponseMessage(HttpStatusCode.OK){
               Content = new ByteArrayContent(ms.ToArray())
                   };
           result.Content.Headers.ContentDisposition =
               new System.Net.Http.Headers.ContentDispositionHeaderValue("attachment") {
               FileName = "Report.pdf"
               };
           result.Content.Headers.ContentType =
               new System.Net.Http.Headers.MediaTypeHeaderValue("application/octet-stream");
           return result;
       }

"Content": {
            "Headers": [
                {
                    "Key": "Content-Disposition",
                    "Value": [
                        "attachment; filename=invoice.pdf"
                    ]
                },
                {
                    "Key": "Content-Type",
                    "Value": [
                        "application/octet-stream"
                    ]
                }
            ]
        },