/default_action
display the images of the parent layout

Sourcecode in LayoutImageMgr/actions.js:
1:   function default_action() {
2:      if (!this._parent.parent) {
3:         res.message = new Exception("layoutNoParent");
4:         res.redirect(this.href());
5:      }
6:      res.data.imagelist = renderList(this._parent.parent.images, "mgrlistitem", 10, req.data.page);
7:      res.data.pagenavigation = renderPageNavigation(this._parent.parent.images, this.href(req.action), 10, req.data.page);
8:      res.data.title = getMessage("LayoutMgr.listParentImagesTitle", {parentLayoutTitle: this._parent.parent.title});
9:      res.data.body = this.renderSkinAsString("main");
10:     res.handlers.context.renderSkin("page");
11:     return;
12:  }