class Asset

def asset_variant(style_name)
  case style_name
  when 'thumbnail'
    asset.variant(gravity: 'Center', resize: '100x100^', crop: '100x100+0+0')
  when 'small'
    asset.variant(gravity: 'Center', resize: '320x320^')
  when 'normal'
    asset.variant(gravity: 'Center', resize_to_limit: [asset.metadata[:width], asset.metadata[:height]])
  when 'icon'
    asset.variant(gravity: 'Center', resize: '50x50^')
  end
end