1. IronPDF
2. How-Tos
3. Generate a PDF with Images from Azure Blob Storage

Rendering PDFs Containing Images Stored in Azure Blob Storage

ByChaknith Bin

January 25, 2023

Updated  June 1, 2025

Share:

Azure Blob Storage is a cloud-based storage service provided by Microsoft Azure. It's designed to store large amounts of unstructured data, such as text or binary data, that can be accessed via HTTP or HTTPS.

Some developers would like to use images stored in Azure Blob Storage. This presents an issue because the image data is stored as binary rather than as a file, which could easily be referenced by HTML. The workaround is to convert images to a base64 string and add them to an img tag.

Get started with IronPDF

Start using IronPDF in your project today with a free trial.

First Step:

Start for Free

Convert Azure Blob to HTML

Assuming you have already set up an Azure Storage account and have a container with blobs, you also need to handle authentication and connection to your Azure Storage in the C# project. Afterward, you can use the DownloadToStreamAsync method to download the image as a stream. The stream information can then be converted to Base64 and embedded in the img tag of HTML. Finally, the imageTag variable can be merged into an HTML document.

using Azure.Storage.Blobs;
using System;
using System.IO;
using System.Threading.Tasks;

public async Task ConvertBlobToHtmlAsync()
{
    // Define your connection string and container name
    string connectionString = "your_connection_string";
    string containerName = "your_container_name";

    // Initialize BlobServiceClient with the connection string
    BlobServiceClient blobServiceClient = new BlobServiceClient(connectionString);

    // Get the BlobContainerClient for the specified container
    BlobContainerClient blobContainer = blobServiceClient.GetBlobContainerClient(containerName);

    // Get the reference to the blob and initialize a stream
    BlobClient blobClient = blobContainer.GetBlobClient("867.jpg");
    using var stream = new MemoryStream();

    // Download the blob data to the stream
    await blobClient.DownloadToAsync(stream);
    stream.Position = 0; // Reset stream position

    // Convert the stream to a byte array
    byte[] array = stream.ToArray();

    // Convert bytes to base64
    var base64 = Convert.ToBase64String(array);

    // Create an img tag with the base64-encoded string
    var imageTag = $"<img src=\"data:image/jpeg;base64,{base64}\"/><br/>";

    // Use the imageTag in your HTML document as needed
}

using Azure.Storage.Blobs;
using System;
using System.IO;
using System.Threading.Tasks;

public async Task ConvertBlobToHtmlAsync()
{
    // Define your connection string and container name
    string connectionString = "your_connection_string";
    string containerName = "your_container_name";

    // Initialize BlobServiceClient with the connection string
    BlobServiceClient blobServiceClient = new BlobServiceClient(connectionString);

    // Get the BlobContainerClient for the specified container
    BlobContainerClient blobContainer = blobServiceClient.GetBlobContainerClient(containerName);

    // Get the reference to the blob and initialize a stream
    BlobClient blobClient = blobContainer.GetBlobClient("867.jpg");
    using var stream = new MemoryStream();

    // Download the blob data to the stream
    await blobClient.DownloadToAsync(stream);
    stream.Position = 0; // Reset stream position

    // Convert the stream to a byte array
    byte[] array = stream.ToArray();

    // Convert bytes to base64
    var base64 = Convert.ToBase64String(array);

    // Create an img tag with the base64-encoded string
    var imageTag = $"<img src=\"data:image/jpeg;base64,{base64}\"/><br/>";

    // Use the imageTag in your HTML document as needed
}

Convert HTML to PDF

Continuing from the imageTag, it can then be converted to PDF by using the RenderHtmlAsPdf method of ChromePdfRenderer.

Below is a simple example of how you might call RenderHtmlAsPdf:

:path=/static-assets/pdf/content-code-examples/how-to/images-azure-blob-storage-html-to-pdf.cs

// Import the IronPdf library to work with PDF rendering.
using IronPdf;

// Create a new instance of the ChromePdfRenderer.
// This object will allow us to render HTML content into a PDF format.
var renderer = new ChromePdfRenderer();

// Define the HTML string that we want to convert to PDF.
// This is the HTML content you want to render as PDF.
var htmlContent = "<html><body><h1>Hello, World!</h1><p>This is a sample HTML to PDF conversion.</p></body></html>";

// Use the renderer to convert the HTML string to a PDF document.
// RenderHtmlAsPdf takes the HTML string as input and returns a PDFDocument object.
var pdfDocument = renderer.RenderHtmlAsPdf(htmlContent);

// Save the resulting PDF document to a file named "imageToPdf.pdf".
// The PDF file will be saved in the current working directory of the application.
pdfDocument.SaveAs("imageToPdf.pdf");

Make sure to adjust the "htmlContent" variable to include your actual HTML content where the imageTag is used.

Chaknith Bin

  Chat with engineering team now

Software Engineer

Chaknith works on IronXL and IronBarcode. He has deep expertise in C# and .NET, helping improve the software and support customers. His insights from user interactions contribute to better products, documentation, and overall experience.