ruby - Image uploads in Rails with jQuery plugins -

i have create prouct page , add photos page. after user creates product redirected page allows them add photos. i'm using jquery file-upload shows preview of pictures selected , upon clicking start adds them server. however, error.

jquery file-upload error

dwadecrop.jpg 97.74 kb error syntaxerror: json.parse: unexpected character

console message

started post "/photos" 127.0.0.1 @ 2013-07-10 21:03:03 -0400 processing photoscontroller#create json parameters: {"utf8"=>"✓", "authenticity_token"=>"tc6sbe9n/ppklzlupqywqxr3c6qjemnqjskr8+prczw=", "product_id"=>"129", "photo"=>{"upload"=>#<actiondispatch::http::uploadedfile:0xa5f0780 @original_filename="dwadecrop.jpg", @content_type="image/jpeg", @headers="content-disposition: form-data; name=\"photo[upload]\"; filename=\"dwadecrop.jpg\"\r\ncontent-type: image/jpeg\r\n", @tempfile=#<file:/tmp/rackmultipart20130710-3967-h6rcoo>>}} product load (0.1ms)  select "products".* "products" "products"."id" = ? limit 1  [["id", "129"]] redirected http://localhost:3000/ completed 302 found in 5ms (activerecord: 0.1ms)   started "/" 127.0.0.1 @ 2013-07-10 21:03:03 -0400 processing staticpagescontroller#home json   rendered static_pages/home.html.haml within layouts/application (1.4ms)   user load (0.3ms)  select "users".* "users" "users"."auth_token" = 'eqoqkrrsnzfa51iidq-90w' limit 1 completed 200 ok in 85ms (views: 84.6ms | activerecord: 0.3ms) 

upload photo view location localhost:3000/products/123/pics

upload file   = form_for @photo, :html => { :multipart => true, :id => "fileupload"  } |f|     = f.file_field :upload     = hidden_field_tag 'product_id', @photo.product_id 

method pics

  def pics     @product = product.find(params[:product_id])     @photo = photo.new     @photo.product_id = @product.id   end 

create method photos

def create   @product = product.find(params[:product_id])   @photo = photo.new    if @photo.valid?     @photo.product_id = @product.id     @photo.save!     respond_to |format|       format.html { redirect_to product_path(@product) }       format.json { render json: @photo }     end   else     redirect_to root_url, :notice => "somehting went wrong!"   end  end 

photo model

class photo < activerecord::base   attr_accessible :image   has_attached_file :image    include rails.application.routes.url_helpers    belongs_to :product     validates_attachment :image, presence: true,                             content_type: { content_type: ['image/jpeg', 'image/jpg', 'image/png', 'image/gif'] },                             size: { less_than: 5.megabytes }     has_attached_file :image, styles: { medium: "320x240>", :thumb => "100x100>"}        def to_jq_image     {       "name" => read_attribute(:upload_file_name),       "size" => read_attribute(:upload_file_size),       "url" => image.url(:original),       "delete_type" => "delete"      }   end  end 

the problem in photo model have

  "name" => read_attribute(:upload_file_name),   "size" => read_attribute(:upload_file_size), 

when model @photo change

  "name" => read_attribute(:photo_file_name),   "size" => read_attribute(:photo_file_size), 

also in form_for have

upload file   = form_for @photo, :html => { :multipart => true, :id => "fileupload"  } |f|     = f.file_field :upload 

where says :upload again model @photo replace well.