title: Image upload using react-admin
body: <p>I am new to react-admin. I am using react-admin to upload the file. I have following the step mentioned below <a href="https://marmelab.com/admin-on-rest/RestClients.html#decorating-your-rest-client-example-of-file-upload" rel="nofollow noreferrer">in tutorial</a>.</p>
  
  <p>But after I submit the request...I see http trace as follow. I see blob link instead of Base64 image payload. </p>
  
  <pre><code>{
      "pictures": {
          "rawFile": {
              "preview": "blob:http://127.0.0.1:3000/fedcd180-cdc4-44df-b8c9-5c7196788dc6"
          },
          "src": "blob:http://127.0.0.1:3000/fedcd180-cdc4-44df-b8c9-5c7196788dc6",
          "title": "Android_robot.png"
      }
  }
  </code></pre>
  
  <p>Can someone please advice how to get base64 image payload instead of link?</p>