Rails: Activerecord : How to send params for I18n message inside errors.add for custom validation

I use Rails 4 with the Rails-i18n Gem and i want replace my hard coded string "300px" with a placeholder in my language translation file like %{minimum_resolution} in config/locales/de.yml

  activerecord:
    errors:
      models:
        organisation:
          attributes:
            image:                 
              resolution_too_small:"Image Resolution should be at least %{minimum_resolution}"

The value in %{minimum_resolution} should come from my custom validation in app/models/organisation.rb

  def validate_minimum_image_dimensions
    if image.present?
      logo = MiniMagick::Image.open(image.path)
      minimum_resolution = 300
      unless logo[:width] > minimum_resolution || logo[:height] > minimum_resolution
        errors.add :image, :minimum_image_size
      end
    else
      return false
    end
  end

How can i get the value from minimum_resolution into my yaml file?

Try this, and let me know

  def validate_minimum_image_dimensions
    if image.present?
      logo = MiniMagick::Image.open(image.path)
      minimum_resolution = 300
      unless logo[:width] > minimum_resolution || logo[:height] > minimum_resolution
        errors.add :image, :resolution_too_small, minimum_resolution: minimum_resolution
      end
    else
      return false
    end
  end

Anyway, this is the syntax

errors.add :field_name, :message_key, {optional_param1: value1, optional_param2: value2}

and it has to be defined like this

  activerecord:
    errors:
      models:
        [your_model]:
          attributes:
            [field_name]:                 
              [message_key]: "Image Resolution should be at least %{optional_param1} and %{optional_param2}"