resizing image with ImageMagick and Rails models

has_attached_file :image,
                  storage: :s3,
                  bucket: ENV['AWS_S3_BUCKET_NAME'],
                  styles: { thumb_filled: '345x345', thumb: '345x345\>' },
                  default_url: '/images/missing_breed.png',
                  convert_options: { thumb_filled: " -background 'rgb(245, 249, 252)' -gravity center -extent 345x345 " }