botframework - Send an image rather than a link

Question

I'm using the Microsoft Bot Framework with Cognitive Services to generate images from a source image that the user uploads via the bot. I'm using C#.

The Cognitive Services API returns a byte[] or a Stream representing the treated image.

How can I send that image directly to my user? All the docs and samples seem to point to me having to host the image as a publically addressable URL and send a link. I can do this but I'd rather not.

Does anyone know how to simple return the image, kind of like the Caption Bot does?

Answer 1

You should be able to use something like this:

var message = activity.CreateReply("");
message.Type = "message";

message.Attachments = new List<Attachment>();
var webClient = new WebClient();
byte[] imageBytes = webClient.DownloadData("https://placeholdit.imgix.net/~text?txtsize=35&txt=image-data&w=120&h=120");
string url = "data:image/png;base64," + Convert.ToBase64String(imageBytes)
message.Attachments.Add(new Attachment { ContentUrl = url, ContentType = "image/png" });
await _client.Conversations.ReplyToActivityAsync(message);