Update: acknowledge the image role

role=`image` is the preferred default role, over the previous and still valid `img` role.

update the spec to call out the existence / allowance of the `image` role.

Author: scottaohara

index.html

@@ -1217,6 +1217,7 @@ <h2 id="docconformance">
                 <a href="#index-aria-application">`application`</a>,
                 <a href="#index-aria-document">`document`</a>,
                 <a href="#index-aria-img">`img`</a>,
+                <a href="#index-aria-img">`image`</a>
                 <a href="#index-aria-none">`none`</a>
                 or <a href="#index-aria-presentation">`presentation`</a>.
               </p>
@@ -1563,6 +1564,7 @@ <h2 id="docconformance">
                 <a href="#index-aria-application">`application`</a>,
                 <a href="#index-aria-document">`document`</a>,
                 <a href="#index-aria-img">`img`</a>,
+                <a href="#index-aria-img">`image`</a>,
                 <a href="#index-aria-none">`none`</a>
                 or <a href="#index-aria-presentation">`presentation`</a>.
               </p>
@@ -1581,7 +1583,7 @@ <h2 id="docconformance">
             <td>
               If the `img` has non-empty [^img/alt^] (`alt="some text"`) or an accessible name is provided another 
               <a data-cite="html-aam-1.0#img-element-accessible-name-computation">`img` naming method</a>:<br>
-              <code>role=<a href="#index-aria-img">img</a></code>
+              <code>role=<a href="#index-aria-img">img or image</a></code>
             </td>
             <td>
               <p>
@@ -1605,7 +1607,7 @@ <h2 id="docconformance">
                 <a href="#index-aria-slider">`slider`</a>,
                 <a href="#index-aria-switch">`switch`</a>,
                 <a href="#index-aria-tab">`tab`</a> or
-                <a href="#index-aria-treeitem">`treeitem`</a>. (<code><a href="#index-aria-img">img</a></code> is also allowed, but NOT RECOMMENDED.)
+                <a href="#index-aria-treeitem">`treeitem`</a>. (<code><a href="#index-aria-img">img or image</a></code> is also allowed, but NOT RECOMMENDED.)
               </p>
               <p>
                 DPub Role:
@@ -1632,7 +1634,7 @@ <h2 id="docconformance">
                 <p id="el-img-no-alt" tabindex="-1">
                   If the `img` <a data-cite="html/images.html#unknown-images">lacks an `alt` attribute</a> and lacks any other 
                   <a data-cite="html-aam-1.0#img-element-accessible-name-computation">`img` naming methods</a>:<br>
-                  <code>role=<a href="#index-aria-img">img</a></code>
+                  <code>role=<a href="#index-aria-img">img or image</a></code>
                 </p>
               </div>
             </td>
@@ -1642,7 +1644,7 @@ <h2 id="docconformance">
                 If the `img` has no `alt` attribute or accessible name:
                 <a><strong class="nosupport">No `role`</strong></a> other than the  
                 <code>role=<a href="#index-aria-none">none</a></code> or <code><a href="#index-aria-presentation">presentation</a></code> roles.
-                (<code>role=<a href="#index-aria-img">img</a></code> is also allowed, but NOT RECOMMENDED.)
+                (<code>role=<a href="#index-aria-img">img or image</a></code> is also allowed, but NOT RECOMMENDED.)
               </p>
               <p>
                 If the `img` has an empty `alt=""` attribute and no `aria-label` or `aria-labelledby` attributes to provide it an accessible name:
@@ -2476,8 +2478,9 @@ <h2 id="docconformance">
               <p>
                 Roles:
                 <a href="#index-aria-application">`application`</a>,
-                <a href="#index-aria-document">`document`</a>
-                or <a href="#index-aria-img">`img`</a>.
+                <a href="#index-aria-document">`document`</a>,
+                <a href="#index-aria-img">`img`</a>
+                or <a href="#index-aria-img">`image`</a>.
               </p>
               <p>
                 <a data-cite="wai-aria-1.2#global_states">Global `aria-*` attributes</a> and
@@ -4416,7 +4419,7 @@ <h2>
         </tr>
         <tr>
           <th tabindex="-1" id="index-aria-img">
-            <a data-cite="wai-aria-1.2#img">`img`</a>
+            <a data-cite="wai-aria-1.2#img">`img` or `image`</a>
           </th>
           <td>
             <ul>