More information....
style sheet has the following icon pointers
.icon-16-shopping { background-image: url(../images/icon-16-shopping.png); }
.icon-48-shopping { background-image: url(../images/icon-48-shopping.png); }
view.html.php has the following pointer to the stylesheet
$doc->addStyleSheet('../media/com_mycomponent/css/admin.stylesheet.css');
and the following toolbar addition
JToolBarHelper::title(JText::_('COM_MYCOMPONENT_TITLE_COMPONENTITEM'), 'shopping.png');
mycomponent.xml manifest has the following administration menu item
<menu img="class:shopping">COM_MYCOMPONENT</menu>
All the above enables the icon to show when the "mycomponent" menu item is selected but when in any other component area the icons don't show.
Any advice and/or guidance greatly appreciated.