```ruby
module Shoppe
  class CustomizationValue < ActiveRecord::Base
    self.table_name = 'shoppe_customization_values'
    belongs_to :customization_type, :class_name => 'Shoppe::CustomizationType'
    has_attached_file :upload, :content_type => ["image/jpg", "image/jpeg", "image/png", "image/gif"]

    include Rails.application.routes.url_helpers

    def to_jq_upload
      {
        "name" => read_attribute(:upload_file_name),
        "size" => read_attribute(:upload_file_size),
        "url" => upload.url(:original),
        "delete_url" => upload_path(self),
        "delete_type" => "DELETE"
      }
    end
  end
end
```

Add new stlye for content type validation
user
```ruby
module Shoppe
  class CustomizationValue < ActiveRecord::Base
    self.table_name = 'shoppe_customization_values'
    belongs_to :customization_type, :class_name => 'Shoppe::CustomizationType'
    has_attached_file :upload
    validates_attachment_content_type :upload, :content_type => /\Aimage/

    include Rails.application.routes.url_helpers

    def to_jq_upload
      {
        "name" => read_attribute(:upload_file_name),
        "size" => read_attribute(:upload_file_size),
        "url" => upload.url(:original),
        "delete_url" => upload_path(self),
        "delete_type" => "DELETE"
      }
    end
  end
end
```
assistant