visibility:visible/hidden div

You can use the show and hide methods:

$(".imageIcon").click(function() {
    $('.imageShowWrapper').show();
});

$(".imageShowWrapper").click(function() {
    $(this).hide();
});

According to your requirement, I believe what you need is as simple as this: http://jsfiddle.net/linmic/6Yadu/

However, using the visibility is different from using show/hide function, gory details: What is the difference between visibility:hidden and display:none?

Another option:

$(".imageIcon, .imageShowWrapper").click(function() {  
    $(".imageShowWrapper").toggle($(this).hasClass('imageIcon'));     
});

You can also use fadeToggle and slideToggle