uploading image to azure blob storage

问题

I know this question can be interpreted as a duplicate, but I can simply not get the blop service working. I have followed the standard example on msdn. I have implemented in my code but followed the example. I can get my MobileService, with the supplied script in the example, to insert a blob with open properties. I then use this code to upload an image to the blob storage:

 BitmapImage bi = new BitmapImage();
 MemoryStream stream = new MemoryStream();
 if (bi != null)
 {
      WriteableBitmap bmp = new WriteableBitmap((BitmapSource)bi);
      bmp.SaveJpeg(stream, bmp.PixelWidth, bmp.PixelHeight, 0, 100);
 }

 if (!string.IsNullOrEmpty(uploadImage.SasQueryString))
 {
       // Get the URI generated that contains the SAS 
       // and extract the storage credentials.
       StorageCredentials cred = new StorageCredentials(uploadImage.SasQueryString);
       var imageUri = new Uri(uploadImage.ImageUri);

       // Instantiate a Blob store container based on the info in the returned item.
       CloudBlobContainer container = new CloudBlobContainer(
       new Uri(string.Format("https://{0}/{1}",
       imageUri.Host, uploadImage.ContainerName)), cred);

       // Upload the new image as a BLOB from the stream.
       CloudBlockBlob blobFromSASCredential = container.GetBlockBlobReference(uploadImage.ResourceName);
       await blobFromSASCredential.UploadFromStreamAsync(stream);//error!

       // When you request an SAS at the container-level instead of the blob-level,
       // you are able to upload multiple streams using the same container credentials.

       stream = null;
 }

I am getting an error in this code at the point marked error, with the following error:

+       ex  {Microsoft.WindowsAzure.Storage.StorageException: The remote server returned an error: NotFound. ---> System.Net.WebException: The remote server returned an error: NotFound. ---> System.Net.WebException: The remote server returned an error: NotFound.

Which I do not understand since the code that returns the string from the script is:

// Generate the upload URL with SAS for the new image.
var sasQueryUrl = blobService.generateSharedAccessSignature(item.containerName, 
item.resourceName, sharedAccessPolicy);

// Set the query string.
item.sasQueryString = qs.stringify(sasQueryUrl.queryString);

// Set the full path on the new new item, 
// which is used for data binding on the client. 
item.imageUri = sasQueryUrl.baseUrl + sasQueryUrl.path;

Of course this also depicts that I do not completely grasp the construction of the blob storage. And therefore any help would be appreciated.

Comment elaborations From the server code it should create a public note for at least 5 minutes. And therefore not be an issue. My server script is the same as the link. But replicated here:

var azure = require('azure');
var qs = require('querystring');
var appSettings = require('mobileservice-config').appSettings;

function insert(item, user, request) {
// Get storage account settings from app settings. 
var accountName = appSettings.STORAGE_ACCOUNT_NAME;
var accountKey = appSettings.STORAGE_ACCOUNT_ACCESS_KEY;
var host = accountName + '.blob.core.windows.net';

if ((typeof item.containerName !== "undefined") && (
item.containerName !== null)) {
    // Set the BLOB store container name on the item, which must be lowercase.
    item.containerName = item.containerName.toLowerCase();

    // If it does not already exist, create the container 
    // with public read access for blobs.        
    var blobService = azure.createBlobService(accountName, accountKey, host);
    blobService.createContainerIfNotExists(item.containerName, {
        publicAccessLevel: 'blob'
    }, function(error) {
        if (!error) {

            // Provide write access to the container for the next 5 mins.        
            var sharedAccessPolicy = {
                AccessPolicy: {
                    Permissions: azure.Constants.BlobConstants.SharedAccessPermissions.WRITE,
                    Expiry: new Date(new Date().getTime() + 5 * 60 * 1000)
                }
            };

            // Generate the upload URL with SAS for the new image.
            var sasQueryUrl = 
            blobService.generateSharedAccessSignature(item.containerName, 
            item.resourceName, sharedAccessPolicy);

            // Set the query string.
            item.sasQueryString = qs.stringify(sasQueryUrl.queryString);

            // Set the full path on the new new item, 
            // which is used for data binding on the client. 
            item.imageUri = sasQueryUrl.baseUrl + sasQueryUrl.path;

        } else {
            console.error(error);
        }

        request.execute();
    });
} else {
    request.execute();
}
}

The idea with the pictures is that other users of the app should be able to access them. As far as I understand I have made it public, but only write public for 5 minutes. The url for the blob I save in a mobileservice table, where the user needs to be authenticated, I would like the same safety on the storage. But do not know if this is accomplished? I am sorry for all the stupid questions, but I have not been able to solve it on my own so I have to "seem" stupid :)