Added JSON sample (#1559)

* Added JSON sample

* Updated JSON sample

Author: IvetNikolova

knowledge-base/preview-reports-using-rest-service-deployed-in-azure.md

@@ -63,6 +63,48 @@ The Reporting engine can be configured to use different output formats for rende
 	</extensions>
 </Telerik.Reporting>
 ````
+````JSON
+"telerikReporting": {
+  "extensions": [
+    {
+      "name": "IMAGEInteractive",
+      "parameters": [
+        {
+          "name": "OutputFormat",
+          "value": "PNG"
+        }
+      ]
+    },
+    {
+      "name": "IMAGE",
+      "parameters": [
+        {
+          "name": "OutputFormat",
+          "value": "PNG"
+        }
+      ]
+    },
+    {
+      "name": "IMAGEPrintPreview",
+      "parameters": [
+        {
+          "name": "OutputFormat",
+          "value": "PNG"
+        }
+      ]
+    },
+    {
+      "name": "IMAGEPrint",
+      "parameters": [
+        {
+          "name": "OutputFormat",
+          "value": "PNG"
+        }
+      ]
+    }
+  ]
+}
+````
 
 ## Additional settings