image_url = 'http://i.ytimg.com/vi/tntOCGkgt98/maxresdefault.jpg'
attachments = attachments = [{'title': 'Cat', 'image_url': image_url}]
sc.api_call('chat.postMessage', channel='D0K7P9MCJ', text=
    'postMessage test', attachments=attachments)
Публикация изображения с помощью Slack API