If you are using carrierwave gem to upload file and you want to add ratio validations for image In the future, we will add more validations

• Validate ratio image by range

class User < ApplicationRecord
  mount_uploader :avatar, AvatarUploader
  validates :avatar, image: { ratio_range: 1..1 }
end

• avatar is your field def
• ratio_range is a option of validate.

Carrierwave Image Validate uses I18n for error messages For this, add these keys in your translation file:

en:
  errors:
    messages:
      aspect_ratio_is_not: "must have an aspect ratio of %{aspect_ratio}"
      aspect_ratio_unknown: "has an unknown aspect ratio"

Add this line to your application's Gemfile:

// require to handle image
gem 'mini_magick', '>= 4.9.5'
// validate
gem 'carrierwave_image_validate'

And then execute

$ bundle

Released under the MIT License. See the LICENSE file for further details.