gpt-4o-vision-datauri.cs

 var chatClient = openAiClient.GetChatClient(deploymentName);

 string dataURI = "data:image/jpeg;base64,<long-data-uri-of-image>";

 //convert data uri to binary data
 byte[] binaryData = Convert.FromBase64String(dataURI.Split(',')[1]);

 List<ChatMessage> messages = [
     new UserChatMessage(
          ChatMessageContentPart.CreateImageMessageContentPart(BinaryData.FromBytes(binaryData), "image/jpeg",
              ImageChatMessageContentPartDetail.High)
          ),
          new UserChatMessage("What is in this image?")
 ];

 ChatCompletion chatCompletion = chatClient.CompleteChat(messages);

 Console.WriteLine($"[ASSISTANT]: {chatCompletion}");

output.md

[ASSISTANT]: The image depicts a dramatic scene of a dragon with red scales and glowing eyes emerging from the clouds. Sunlight beams illuminate the creature, highlighting its sharp features and wings. The setting gives a mystical and powerful atmosphere.