Image broken when uploaded to Azure blobs

Question

I'm using following code to upload an image to Azure blob storage. Image is uploaded to the storage but it's broken. Following is my code. The Base64 string is correct and I have confirmed it.

string match_val = "z5FuyuNiJDbbb...................";

System.Drawing.Bitmap img = Custom.ConertBase64ToFile(match_val);

var bytes = Convert.FromBase64String(match_val);

StorageCredentials creden = new StorageCredentials(accountname, accesskey);
CloudStorageAccount acc = new CloudStorageAccount(creden, useHttps: true);
CloudBlobClient client = acc.CreateCloudBlobClient();

CloudBlobContainer cont = client.GetContainerReference(container);
 await cont.CreateIfNotExistsAsync();

await cont.SetPermissionsAsync(new BlobContainerPermissions
{
    PublicAccess = BlobContainerPublicAccessType.Blob
});

CloudBlockBlob cblob = cont.GetBlockBlobReference(Path.Combine(ProfileSignaturePath, string.Concat(fileName, ".", FileFormat.png)).Replace(@"\","/"));

cblob.Properties.ContentType = "image/png";

using (System.Drawing.Image image = System.Drawing.Image.FromStream(new MemoryStream(bytes), true, true))
{
    using (MemoryStream memoryStream = new MemoryStream())
    {
        image.Save(memoryStream, System.Drawing.Imaging.ImageFormat.Png);
        await cblob.UploadFromStreamAsync(memoryStream);
        blobUrl = cblob.Uri.AbsoluteUri;
    }
}

string resUrl = blobUrl;

This is what the browser shows

Blob image url is https://mspmatefilestorage.blob.core.windows.net/production/Resources/ProfilePictures/Signatures/signature_16.png

Is there any issues in my image upload code?

Answer 1

May I know what the match_val is? Is it a base64 encoded string of the png file content?

I quickly created a console project and everything worked fine. Here is my sample:

    class Program
    {
        static string storageAccountName = "storagetest789";
        static string storageAccountKey = "G36mc********Zup3h9kzj1w==";
        static void Main(string[] args)
        {
            string match_val  = null;
            using(FileStream fileStream = File.Open(@"D:\User\Pictures\test.png",FileMode.Open))
            using(MemoryStream memoryStream = new MemoryStream()){
                fileStream.CopyTo(memoryStream);
                match_val  = Convert.ToBase64String(memoryStream.ToArray());
            }

            StorageCredentials storageCredentials = new StorageCredentials(storageAccountName,storageAccountKey);
            CloudStorageAccount cloudStorageAccount = new CloudStorageAccount(storageCredentials, true);
            CloudBlobClient cloudBlobClient = cloudStorageAccount.CreateCloudBlobClient();
            CloudBlobContainer cloudBlobContainer = cloudBlobClient.GetContainerReference("pub"); // For convenience, it is a public container, so I do not need to set access permission
            cloudBlobContainer.CreateIfNotExists();
            CloudBlockBlob cloudBlockBlob = cloudBlobContainer.GetBlockBlobReference("test2.png");

            using(MemoryStream memoryStream = new MemoryStream(Convert.FromBase64String(match_val)))
            using(Image image = Image.FromStream(memoryStream,true,true))
            using(CloudBlobStream cloudBlobStream = cloudBlockBlob.OpenWrite()){
                image.Save(cloudBlobStream, System.Drawing.Imaging.ImageFormat.Png);
            }

            Console.WriteLine(cloudBlockBlob.Uri.AbsoluteUri);
            Console.ReadLine();
        }
    }

I did not have a base64 encoded string. So I generated one in the code. The differences were that:

1. I just opened an output stream by cloudBlockBlob.OpenWrite()
2. Then I used image.Save method to directly save image contents to the blob stream.

Finally, I got an url: https://storagetest789.blob.core.windows.net/pub/test2.png

And I was able to view the image in browser: