IMessage is not the resulted image, rather it contains image. Here is the correct code sample.if (message.Name == "ExportMapImageResponse"){ IXMLSerializeData requestParams = message.Parameters; int resultIndex = requestParams.Find("Result"); IImageResult Result =(IImageResult)requestParams.GetObject(resultIndex, message.NamespaceURI, "Result"); byte[] imageResponse = Result.MimeData; IsByteArrayValid(imageResponse);}