Validate dropify with jquery

[OriginersMc]

Hi!

I want validate file name format to prevent files names like "this.is.an.image.png". I have jquery validation on my page and the next jquery validate script:

<script>
    $.validator.addMethod("checkFileName", function(value, element) { 
        return this.optional(element) || /\\([a-z0-9])*\.(jpg|png|jpeg)/i.test(value); 
    }, "El nombre de la imagen no puede tener puntos.");
    var $validator = $("#editarCabecera").validate({ 
        errorClass: "is-invalid",
        errorElement: "errorLabel",
        validClass: "is-valid",
        rules: {
            textoGrande: {
                required: true
            },
            imagen: {
                required: true,
                checkFileName: true
            }
        },
        messages: {
            textoGrande: {
                required: ""
            },
            imagen: {
                required: ""
            }
        }
    });
</script>   

How I can apply this check to dropify ?