Unselect checkbox at click using Jquery

I set up a basic shopping cart where you have to put goods into a green box to order them. When you click on the item icon, it correctly checks the associated checkbox. Unfortunately, when you click again on it, it doesn't uncheck.

I've tried `$(elem).prop('checked', false); but it doesn't work. Do you have any other idea please?

JSFiddle: http://ift.tt/1vy7YDh (I've let the checkbox displayed on to let you see the bug).

Code:

html

<div id="selected"></div>

    <div id="nonSelected">

      <label for="blackjack"><img onclick="moveButton(this)" src="http://ift.tt/1CYpQoi" alt="" data-checked='img/blackjack.gif' data-unchecked='img/blackjack.jpg'></label>
      <INPUT id="blackjack" type="checkbox" value="Blackjack" name="game[]">    

      <label for="chuckaluck"><img onclick="moveButton(this)" src="http://ift.tt/19WTbbK" alt="" data-checked='img/chuckaluck.gif' data-unchecked='img/chuckaluck.jpg'></label>
      <INPUT id="chuckaluck" type="checkbox" value="Chuck a Luck" name="game[]">

      <label for="roulette"><img onclick="moveButton(this)" src="http://ift.tt/1CYpQok" alt="" data-checked='img/roulette.gif' data-unchecked='img/roulette.jpg'></label>
      <INPUT id="roulette" type="checkbox" value="Roulette" name="game[]">

      <label for="stud"><img onclick="moveButton(this)" src="http://ift.tt/19WT9k7" alt="" data-checked='img/stud.gif' data-unchecked='img/stud.jpg'></label>
      <INPUT id="stud" type="checkbox" value="Stud Poker" name="game[]">

      <label for="holdem"><img onclick="moveButton(this)" src="http://ift.tt/1CYpRIW" alt="" data-checked='img/holdem.gif' data-unchecked='img/holdem.jpg'></label>
      <INPUT id="holdem" type="checkbox" value="Holdem Poker" name="game[]">

      <label for="boule"><img onclick="moveButton(this)" src="http://ift.tt/19WTbbU" alt="" data-checked='img/boule.gif' data-unchecked='img/boule.jpg'></label>
      <INPUT id="boule" type="checkbox" value="La Boule" name="game[]">

  </div>

js

function moveButton(elem){
    if( $(elem).closest("div").attr("id") == "nonSelected" ){
        $(elem).prependTo('#selected');
    }
    else{
        $(elem).prependTo('#nonSelected');
    }
}

css

#selected{
    width: 400px;
    height: 200px;
    background-color: #339933;
    border-width: 1px;
    border-style: dotted;
    border-color: black;
    padding: 10px;
    margin: 10px;
}

img{
    cursor: pointer;
}