input[type="checkbox"][img] {
    display:none;
}
input[type="checkbox"][img] + label span {
    display:inline-block;
    width:28px;
    height:28px;
    vertical-align:middle;
    background:url("/img_work/check_off.png") left top no-repeat;
    cursor:pointer;
}
input[type="checkbox"][img]:checked + label span {
    background:url("/img_work/check_on.png") left top no-repeat;
}

input[mark][type="checkbox"]{
    -webkit-appearance: initial;
    appearance: initial;
    cursor:pointer;
    width: 15px;
    height: 15px;
    /* border: 1px solid #000000; */
    border: none;
    position: relative;
}
input[mark][type="checkbox"]:checked {
}
input[mark][type="checkbox"]:checked:after {
    /* Heres your symbol replacement */
    content: "✘";
    color: red;
    position: absolute;
    left: 50%;
    top: 50%;
    -webkit-transform: translate(-50%,-50%);
    -moz-transform: translate(-50%,-50%);
    -ms-transform: translate(-50%,-50%);
    transform: translate(-50%,-50%);
}