Dropzone.js image resolution validation

var minImageWidth = 800,
          minImageHeight = 600;
          Dropzone.options.graphicDropzone = {
            maxFilesize: 3,
            maxFiles: 3,
            addRemoveLinks: true,
            acceptedFiles: ".psd, .ai, .jpg, .jpeg, .gif, .png",
            init: function() {
              this.on("success", function(file, responseText) {
                file.previewTemplate.setAttribute('id',responseText[0].id);
              });
              this.on("thumbnail", function(file) {
                if (file.width < minImageWidth || file.height < minImageHeight) {
                  file.rejectDimensions()
                }
                else {
                  file.acceptDimensions();
                }
              });
            },
            accept: function(file, done) {
              file.acceptDimensions = done;
              file.rejectDimensions = function() { done("Image too small."); };
            }
          };