Create ImageFileUpload.md

Original file: Sample18_PersistentAgents_ImageFileInputs.md
Fixed up example and added the file upload cleanup that was missing.

Author: RobiladK

doc-samples/agents/c#/azure-ai-agent-sdk/ImageFileUpload.md

@@ -0,0 +1,209 @@
+# Sample using agents with Image File as an input in Azure.AI.Agents
+
+Demonstrates examples of sending an image file (along with optional text) as a structured content block in a single message. The examples shows how to create an agent, open a thread, post content blocks combining text and image inputs, and then run the agent to see how it interprets the multimedia input.
+
+1. First get `ProjectEndpoint` and `ModelDeploymentName` from config and create a `PersistentAgentsClient`.
+
+```C# Snippet:AgentsImageFileInMessageCreateClient
+var projectEndpoint = configuration["ProjectEndpoint"];
+var modelDeploymentName = configuration["ModelDeploymentName"];
+PersistentAgentsClient client = new(new Uri(projectEndpoint), new DefaultAzureCredential());
+```
+
+2. Upload a file for referencing in your message:
+
+Synchronous sample:
+```C# Snippet:AgentsImageFileInMessageUpload_Sync
+var completeFilePath = "C:\\Users\\username\\Downloads\\image.jpg";
+
+PersistentAgentFile uploadedFile = client.UploadFile(
+    filePath: completeFilePath,
+    purpose: PersistentAgentFilePurpose.Agents
+);
+```
+
+Asynchronous sample:
+```C# Snippet:AgentsImageFileInMessageUpload
+var completeFilePath = "C:\\Users\\username\\Downloads\\image.jpg";
+
+PersistentAgentFile uploadedFile = await client.UploadFileAsync(
+    filePath: completeFilePath,
+    purpose: PersistentAgentFilePurpose.Agents
+);
+```
+
+3. Create an agent.
+
+Synchronous sample:
+```C# Snippet:AgentsImageFileInMessageCreateAgent_Sync
+PersistentAgent agent = client.CreateAgent(
+    model: modelDeploymentName,
+    name: "File Image Understanding Agent",
+    instructions: "Analyze images from internally uploaded files."
+);
+```
+
+Asynchronous sample:
+```C# Snippet:AgentsImageFileInMessageCreateAgent
+PersistentAgent agent = await client.CreateAgentAsync(
+    model: modelDeploymentName,
+    name: "File Image Understanding Agent",
+    instructions: "Analyze images from internally uploaded files."
+);
+```
+
+4. Create a thread.
+
+Synchronous sample:
+```C# Snippet:AgentsImageFileInMessageCreateThread_Sync
+PersistentAgentThread thread = client.CreateThread();
+```
+
+Asynchronous sample:
+```C# Snippet:AgentsImageFileInMessageCreateThread
+PersistentAgentThread thread = await client.CreateThreadAsync();
+```
+
+5. Create a message referencing the uploaded file.
+
+Synchronous sample:
+```C# Snippet:AgentsImageFileInMessageCreateMessage_Sync
+var contentBlocks = new List<MessageInputContentBlock>
+{
+    new MessageInputTextBlock("Here is an uploaded file. Please describe it:"),
+    new MessageInputImageFileBlock(new MessageImageFileParam(uploadedFile.Id))
+};
+
+client.CreateMessage(
+    threadId: thread.Id,
+    role: MessageRole.User,
+    contentBlocks: contentBlocks
+);
+```
+
+Asynchronous sample:
+```C# Snippet:AgentsImageFileInMessageCreateMessage
+var contentBlocks = new List<MessageInputContentBlock>
+{
+    new MessageInputTextBlock("Here is an uploaded file. Please describe it:"),
+    new MessageInputImageFileBlock(new MessageImageFileParam(uploadedFile.Id))
+};
+
+await client.CreateMessageAsync(
+    thread.Id,
+    MessageRole.User,
+    contentBlocks: contentBlocks
+);
+```
+
+6. Run the agent.
+
+Synchronous sample:
+```C# Snippet:AgentsImageFileInMessageCreateRun_Sync
+ThreadRun run = client.CreateRun(
+    threadId: thread.Id,
+    assistantId: agent.Id
+);
+```
+
+Asynchronous sample:
+```C# Snippet:AgentsImageFileInMessageCreateRun
+ThreadRun run = await client.CreateRunAsync(
+    threadId: thread.Id,
+    assistantId: agent.Id
+);
+```
+
+7. Wait for the run to complete.
+
+Synchronous sample:
+```C# Snippet:AgentsImageFileInMessageWaitForRun_Sync
+do
+{
+    Thread.Sleep(500);
+    run = client.GetRun(thread.Id, run.Id);
+}
+while (run.Status == RunStatus.Queued
+    || run.Status == RunStatus.InProgress);
+```
+
+Asynchronous sample:
+```C# Snippet:AgentsImageFileInMessageWaitForRun
+do
+{
+    await Task.Delay(500);
+    run = await client.GetRunAsync(thread.Id, run.Id);
+}
+while (run.Status == RunStatus.Queued
+    || run.Status == RunStatus.InProgress);
+```
+
+8. Retrieve messages (including any agent responses) and print them.
+
+Synchronous sample:
+```C# Snippet:AgentsImageFileInMessageReview_Sync
+PageableList<ThreadMessage> messages = client.GetMessages(
+    thread.Id,
+    order: ListSortOrder.Ascending);
+
+foreach (ThreadMessage threadMessage in messages)
+{
+    foreach (MessageContent content in threadMessage.ContentItems)
+    {
+        switch (content)
+        {
+            case MessageTextContent textItem:
+                Console.Write($"{threadMessage.Role}: {textItem.Text}");
+                Console.WriteLine();
+                break;
+
+            case MessageImageFileContent fileItem:
+                Console.WriteLine($"{threadMessage.Role}:  Image File (internal ID): {fileItem.FileId}");
+                Console.WriteLine();
+                break;
+        }
+    }
+}
+```
+
+Asynchronous sample:
+```C# Snippet:AgentsImageFileInMessageReview
+PageableList<ThreadMessage> messages = await client.GetMessagesAsync(
+    thread.Id,
+    order: ListSortOrder.Ascending);
+
+foreach (ThreadMessage threadMessage in messages)
+{
+    foreach (MessageContent content in threadMessage.ContentItems)
+    {
+        switch (content)
+        {
+            case MessageTextContent textItem:
+                Console.Write($"{threadMessage.Role}: {textItem.Text}");
+                Console.WriteLine();
+                break;
+
+            case MessageImageFileContent fileItem:
+                Console.WriteLine($"{threadMessage.Role}:  Image File (internal ID): {fileItem.FileId}");
+                Console.WriteLine();
+                break;
+        }
+    }
+}
+```
+
+9. Finally, we delete all the resources, we have created in this sample.
+
+Synchronous sample:
+```C# Snippet:AgentsImageFileInMessageCleanup_Sync
+client.DeleteThread(thread.Id);
+client.DeleteAgent(agent.Id);
+client.DeleteFile(uploadedFile.Id);
+```
+
+Asynchronous sample:
+```C# Snippet:AgentsImageFileInMessageCleanup
+await client.DeleteFileAsync(uploadedFile.Id);
+await client.DeleteThreadAsync(thread.Id);
+await client.DeleteAgentAsync(agent.Id);
+```