Question

Is possible with carrierwave create a version (for example thumb) only if the image is larger than the size of the version??

Example:

version :thumb, :if => :is_thumbnable? do 
    process :resize_to_fit => [32,nil]
end

protected

def is_thumbnable?(file)
  image ||= MiniMagick::Image.open(file.path)
  if image.nil?
    if image['width'] >= 32 || image['height'] >= 32
      true
    else
      false
    end
  else
    false
  end
end

Answer 1

I defined method in which if image exceed given width then manipulate it to your size the 32 pixels in this case. Put this code in your ImageUploader:

  version :thumb do 
    process :resize_to_width => [32, nil]
  end

  def resize_to_width(width, height)
    manipulate! do |img|
      if img[:width] >= width
        img.resize "#{width}x#{img[:height]}"
      end
      img = yield(img) if block_given?
      img
    end
  end