fight with styling to make the button at least appear

app/assets/stylesheets/application.scss.erb

@@ -2052,6 +2052,26 @@ and it won't be important on password protected instances */
 .yourMap .mapInfoDelete {
     display: block;
 }
+
+.mapInfoButtonsWrapper .mapInfoThumbnail {
+  display: block;
+  background-image: url(<%= asset_path('screenshot_sprite.png') %>);
+  width: 32px;
+  height: 32px;
+
+  .tooltip {
+    display: none;
+  }
+
+  &:hover {
+    background-position: -32px 0;
+
+    .tooltip {
+      display: block;
+    }
+  }
+}
+
 .mapInfoButtonsWrapper span {
     position: absolute;
     width: 100%;

app/views/layouts/_templates.html.erb

@@ -36,7 +36,7 @@
       <div class="mapInfoButtonsWrapper">
         <div class="mapInfoThumbnail">
           <div class="thumbnail"></div>
-          <span>Update Thumbnail</span>
+          <div class="tooltip">Update Thumbnail</div>
         </div>
         <div class="mapInfoDelete">
           <div class="deleteMap"></div>

app/views/maps/_mapinfobox.html.erb

@@ -77,6 +77,10 @@
     <p class="mapCreatedAt"><span>Created by:</span> <%= @map.user == user ? "You" : @map.user.name %> on <%= @map.created_at.strftime("%m/%d/%Y") %></p>
     <p class="mapEditedAt"><span>Last edited:</span> <%= @map.updated_at.strftime("%m/%d/%Y") %></p>
     <div class="mapInfoButtonsWrapper">
+      <div class="mapInfoThumbnail">
+        <div class="thumbnail"></div>
+        <div class="tooltip">Update Thumbnail</div>
+      </div>
       <div class="mapInfoDelete">
         <div class="deleteMap"></div>
         <span>Delete</span>