set the size of the icon in CSS to avoid table re-layout

core/src/main/resources/lib/hudson/ballColorTd.jelly

@@ -34,7 +34,7 @@ THE SOFTWARE.
   <td data="${it.ordinal()}">
     <j:if test="${attrs.it!=null}">
       <img src="${it.getImageOf(iconSize)}" alt="${it.description}"
-           tooltip="${it.description}" style="${attrs.style}"/>
+           tooltip="${it.description}" style="${attrs.style}" class="icon${iconSize}"/>
     </j:if>
   </td>
 </j:jelly>

war/src/main/webapp/css/style.css

@@ -481,6 +481,22 @@ div.behavior-loading {
     background-position: left center;
     background-repeat: no-repeat;
 }
+
+.icon16x16 {
+    width: 16px;
+    height: 16px;
+}
+
+.icon24x24 {
+    width: 24px;
+    height: 24px;
+}
+
+.icon32x32 {
+    width: 32px;
+    height: 32px;
+}
+
 /* ====================== help ===================================== */
 
 .help {