/main_action
display all images of a site or layout

Sourcecode in LayoutImageMgr/actions.js:
1:   function main_action() {
2:      res.data.imagelist = renderList(this.mergeImages(), "mgrlistitem", 10, req.data.page);
3:      res.data.pagenavigation = renderPageNavigation(this, this.href(), 10, req.data.page);
4:      res.data.title = getMessage("LayoutMgr.mainTitle", {layoutTitle: this._parent.title});
5:      res.data.body = this.renderSkinAsString("main");
6:      res.handlers.context.renderSkin("page");
7:      return;
8:   }