diff --git a/api-ref/src/docbkx/ch_images-v2.xml b/api-ref/src/docbkx/ch_images-v2.xml
index 0667fc92c..065b95fb0 100644
--- a/api-ref/src/docbkx/ch_images-v2.xml
+++ b/api-ref/src/docbkx/ch_images-v2.xml
@@ -30,8 +30,9 @@
         <title>Images</title>
         <para>Creates, lists, updates, and deletes images.</para>
         <para>
-            Image operations show all fields in the response body. For any
-            field with no value, the response body shows <code>None</code>.
+            Image operations show all fields in the response body. Any field
+            with no value is set to <code>null</code> value (JSON null data
+            type).
         </para>
         <para>
             The possible status values for images are:
diff --git a/api-ref/src/wadls/image-api/src/v2/common.ent b/api-ref/src/wadls/image-api/src/v2/common.ent
index 42381f821..4fa4b439c 100644
--- a/api-ref/src/wadls/image-api/src/v2/common.ent
+++ b/api-ref/src/wadls/image-api/src/v2/common.ent
@@ -236,8 +236,8 @@
 <wadl:doc xmlns="http://docbook.org/ns/docbook"
    xmlns:wadl="http://wadl.dev.java.net/2009/02" xml:lang="EN">
    <para>The name of the image.</para>
-   <para>If this field has no value, its
-      value is <code>None</code>.
+   <para>
+      If this field has no value, its value is <code>null</code> (JSON null data type).
    </para>
 </wadl:doc>
 </param>'>
@@ -250,8 +250,8 @@
    <para>
       The container format of image.
    </para>
-   <para>If this field has no value, its
-      value is <code>None</code>.
+   <para>
+      If this field has no value, its value is <code>null</code> (JSON null data type).
    </para>
 </wadl:doc>
 </param>'>
@@ -272,7 +272,7 @@
       The disk format of the image.
    </para>
    <para>
-      If this field has no value, its value is <code>None</code>.
+      If this field has no value, its value is <code>null</code> (JSON null data type).
    </para>
 </wadl:doc>
 </param>'>
@@ -289,9 +289,11 @@
    style="plain" required="true" type="xsd:int">
 <wadl:doc xmlns="http://docbook.org/ns/docbook"
    xmlns:wadl="http://wadl.dev.java.net/2009/02" xml:lang="EN">
-   <para>The minimum disk size in GB that is required to boot the image.</para>
    <para>
-      If this field has no value, its value is <code>None</code>.
+      The minimum disk size in GB that is required to boot the image.
+   </para>
+   <para>
+      If this field has no value, its value is <code>null</code> (JSON null data type).
    </para>
 </wadl:doc>
 </param>'>
@@ -317,8 +319,8 @@
 <wadl:doc xmlns="http://docbook.org/ns/docbook"
    xmlns:wadl="http://wadl.dev.java.net/2009/02" xml:lang="EN">
    <para>The minimum amount of RAM in MB that is required to boot the image.</para>
-   <para>If this field has no value, its
-      value is <code>None</code>.
+   <para>
+      If this field has no value, its value is <code>null</code> (JSON null data type).
    </para>
 </wadl:doc>
 </param>'>
@@ -330,8 +332,8 @@
    <para>Hash of the image data used. The Image service uses this value for
       verification.
    </para>
-   <para>If this field has no value, its
-      value is <code>None</code>.
+   <para>
+      If this field has no value, its value is <code>null</code> (JSON null data type).
    </para>
 </wadl:doc>
 </param>'>
@@ -341,8 +343,8 @@
 <wadl:doc xmlns="http://docbook.org/ns/docbook"
    xmlns:wadl="http://wadl.dev.java.net/2009/02" xml:lang="EN">
    <para>The ID of the owner, or tenant, of the image.</para>
-   <para>If this field has no value, its
-      value is <code>None</code>.
+   <para>
+      If this field has no value, its value is <code>null</code> (JSON null data type).
    </para>
 </wadl:doc>
 </param>'>
@@ -360,8 +362,8 @@
 <wadl:doc xmlns="http://docbook.org/ns/docbook"
    xmlns:wadl="http://wadl.dev.java.net/2009/02" xml:lang="EN">
    <para>The virtual size of the image.</para>
-   <para>If this field has no value, its
-      value is <code>None</code>.
+   <para>
+      If this field has no value, its value is <code>null</code> (JSON null data type).
    </para>
 </wadl:doc>
 </param>'>
@@ -379,8 +381,8 @@
 <wadl:doc xmlns="http://docbook.org/ns/docbook"
    xmlns:wadl="http://wadl.dev.java.net/2009/02" xml:lang="EN">
    <para>The size of the image data, in bytes.</para>
-   <para>If this field has no value, its
-      value is <code>None</code>.
+   <para>
+      If this field has no value, its value is <code>null</code> (JSON null data type).
    </para>
 </wadl:doc>
 </param>'>
diff --git a/api-ref/src/wadls/image-api/src/v2/samples/image-create-response.json b/api-ref/src/wadls/image-api/src/v2/samples/image-create-response.json
index aa679dc39..2b362d3bb 100644
--- a/api-ref/src/wadls/image-api/src/v2/samples/image-create-response.json
+++ b/api-ref/src/wadls/image-api/src/v2/samples/image-create-response.json
@@ -18,7 +18,7 @@
     "owner": "b4eedccc6fb74fa8a7ad6b08382b852b",
     "min_ram": 0,
     "schema": "/v2/schemas/image",
-    "size": "None",
-    "checksum": "None",
-    "virtual_size": "None"
+    "size": null,
+    "checksum": null,
+    "virtual_size": null
 }
diff --git a/api-ref/src/wadls/image-api/src/v2/samples/image-details-deactivate-response.json b/api-ref/src/wadls/image-api/src/v2/samples/image-details-deactivate-response.json
index 1180fd363..43d41c335 100644
--- a/api-ref/src/wadls/image-api/src/v2/samples/image-details-deactivate-response.json
+++ b/api-ref/src/wadls/image-api/src/v2/samples/image-details-deactivate-response.json
@@ -17,5 +17,5 @@
     "size": 13167616,
     "min_ram": 0,
     "schema": "/v2/schemas/image",
-    "virtual_size": "None"
+    "virtual_size": null
 }
diff --git a/api-ref/src/wadls/image-api/src/v2/samples/image-details-response.json b/api-ref/src/wadls/image-api/src/v2/samples/image-details-response.json
index c425508f5..07055355c 100644
--- a/api-ref/src/wadls/image-api/src/v2/samples/image-details-response.json
+++ b/api-ref/src/wadls/image-api/src/v2/samples/image-details-response.json
@@ -17,5 +17,5 @@
     "size": 13167616,
     "min_ram": 0,
     "schema": "/v2/schemas/image",
-    "virtual_size": "None"
+    "virtual_size": null
 }
diff --git a/api-ref/src/wadls/image-api/src/v2/samples/image-list-response.json b/api-ref/src/wadls/image-api/src/v2/samples/image-list-response.json
index ded242eac..8e2097a09 100644
--- a/api-ref/src/wadls/image-api/src/v2/samples/image-list-response.json
+++ b/api-ref/src/wadls/image-api/src/v2/samples/image-list-response.json
@@ -19,7 +19,7 @@
             "size": 13167616,
             "min_ram": 0,
             "schema": "/v2/schemas/image",
-            "virtual_size": "None"
+            "virtual_size": null
         },
         {
             "status": "active",
@@ -40,7 +40,7 @@
             "size": 476704768,
             "min_ram": 0,
             "schema": "/v2/schemas/image",
-            "virtual_size": "None"
+            "virtual_size": null
         }
     ],
     "schema": "/v2/schemas/images",
diff --git a/api-ref/src/wadls/image-api/src/v2/samples/image-update-response.json b/api-ref/src/wadls/image-api/src/v2/samples/image-update-response.json
index a360ba5f2..2fdcdd90f 100644
--- a/api-ref/src/wadls/image-api/src/v2/samples/image-update-response.json
+++ b/api-ref/src/wadls/image-api/src/v2/samples/image-update-response.json
@@ -14,10 +14,10 @@
     "self": "/v2/images/da3b75d9-3f4a-40e7-8a2c-bfab23927dea",
     "file": "/v2/images/da3b75d9-3f4a-40e7-8a2c-bfab23927dea/file",
     "schema": "/v2/schemas/image",
-    "owner": "None",
-    "min_ram": "None",
-    "min_disk": "None",
-    "disk_format": "None",
-    "virtual_size": "None",
-    "container_format": "None"
+    "owner": null,
+    "min_ram": null,
+    "min_disk": null,
+    "disk_format": null,
+    "virtual_size": null,
+    "container_format": null
 }