```ruby
class Snapshot < ActiveRecord::Base
  belongs_to :url
  belongs_to :diffed_with_snapshot, class_name: Snapshot.name
  validates_presence_of :url
  default_scope { order('created_at DESC') }

  def image_name
    external_image_id + '.png'
  end

  def diff_image_name
    diff_external_image_id + '.png'
  end

  def diff?
    !!diffed_with_snapshot
  end

  def sample_image_url
    # TODO: how do I get access to helper methods here? (`cl_image_path`)

    # Use max 1500 high images, to speed up diff
    "http://res.cloudinary.com/diffux/image/upload/c_fit,h_1000/v1375678803/#{image_name}"
  end

  def baseline_for_url?
    url.baseline.try(:snapshot) == self
  end
end
```

Use Cloudinary helper to generate `sample_image_url`
user
```ruby
class Snapshot < ActiveRecord::Base
  belongs_to :url
  belongs_to :diffed_with_snapshot, class_name: Snapshot.name
  validates_presence_of :url
  default_scope { order('created_at DESC') }

  def image_name
    external_image_id + '.png'
  end

  def diff_image_name
    diff_external_image_id + '.png'
  end

  def diff?
    !!diffed_with_snapshot
  end

  def sample_image_url
    Cloudinary::Utils.cloudinary_url(image_name,
                                     height: 1000, crop: :fit)
  end

  def baseline_for_url?
    url.baseline.try(:snapshot) == self
  end
end
```
assistant