Jquery validate file upload validation

 $("#fileForm").validate({
              rules: {
                //any other rules go here
              }
            });

$('.your-dozen-fields-selector').rules("add", {
 required: false,
 accept: "png,jpg,jpeg,pdf"
});

HTML

<input type="file" placeholder="" name="poster" accept="image/*">

rules:{
    poster :{
         required : true,
         accept: "png,jpg,jpeg,gif"    }
},
   messages: {
    category_id__sub_category_id: 'Please select category',
    seller_name: 'Please enter seller name',
    email: {
        required: 'Please enter email',
        email: 'Please enter valid email id',
    },poster:{
        accept : 'Please upload PNG, JPG, or GIF only'    }