.myCheckbox input {
    display: none;
}

.myCheckbox span {
	width: 116px;
	height: 18px;
	display: block;
	background-image: url(../Pics/remember_me_unchecked.png);
}

.myCheckbox input:checked + span {
	background-image: url(../Pics/remember_me_checked.png);
}