Erratum for Example 79 to correct width and height properties

Example 79 includes an Image with width and height properties that are only allowed for Link objects. This erratum changes the example to move the width and height to the url property.

Author: evanp

ERRATA.md

@@ -108,6 +108,30 @@ This document includes errata for the [Activity Streams](https://www.w3.org/TR/a
 
 - The domain of the `attributedTo` property is both `Link` and `Object`. `attributedTo` should be included in the list of properties of a `Link`.
 
+  - Example 79 has  an `Image` object with `width` and `height` properties, which
+    are only allowed on `Link` objects. One alternative is to use a `Link` object
+    with the correct `height` and `width` as the `url` property for each `Image`
+    object.
+
+    ```json
+    {
+      "@context": "https://www.w3.org/ns/activitystreams",
+      "summary": "A simple note",
+      "type": "Note",
+      "content": "This is all there is.",
+      "icon": {
+        "type": "Image",
+        "name": "Note icon",
+        "url": {
+           "href": "http://example.org/note.png",
+           "type": "Link",
+           "width": 16,
+           "height": 16
+        }
+      }
+    }
+    ```
+
 - The Notes for the `to` property do not correctly identify the functionality (one or more) of the values of the property. The notes should read: "Identifies one or more entities that are part of the public primary audience of this Object."
 
 - The Notes for the `bto` property do not correctly identify the functionality (one or more) of the values of the property. The notes should read: "Identifies one or more entities that are part of the private primary audience of this Object."