Create ImageUrlInput.md

Original: Sample17_PersistentAgents_ImageUrlInputs.md. Made sure it works with uri and made it consistent with other samples.

Author: RobiladK

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

@@ -0,0 +1,194 @@
+# Sample using agents with Image URL as an input in Azure.AI.Agents
+
+This sample demonstrates examples of sending an image URL (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:AgentImageUrlInMessageCreateClient
+var projectEndpoint = configuration["ProjectEndpoint"];
+var modelDeploymentName = configuration["ModelDeploymentName"];
+PersistentAgentsClient client = new(new Uri(projectEndpoint), new DefaultAzureCredential());
+```
+
+2. Create an agent.
+
+Synchronous sample:
+```C# Snippet:AgentImageUrlInMessageCreateAgent_Sync
+PersistentAgent agent = client.CreateAgent(
+    model: modelDeploymentName,
+    name: "Image Understanding Agent",
+    instructions: "You are an image-understanding agent. Analyze images and provide textual descriptions."
+);
+```
+
+Asynchronous sample:
+```C# Snippet:AgentImageUrlInMessageCreateAgent
+PersistentAgent agent = await client.CreateAgentAsync(
+    model: modelDeploymentName,
+    name: "Image Understanding Agent",
+    instructions: "You are an image-understanding agent. Analyze images and provide textual descriptions."
+);
+```
+
+3. Create a thread
+
+Synchronous sample:
+```C# Snippet:AgentImageUrlInMessageCreateThread_Sync
+PersistentAgentThread thread = client.CreateThread();
+```
+
+Asynchronous sample:
+```C# Snippet:AgentImageUrlInMessageCreateThread
+PersistentAgentThread thread = await client.CreateThreadAsync();
+```
+
+4. Create a message using multiple content blocks. Here we combine a short text and an image URL in a single user message.
+
+Synchronous sample:
+```C# Snippet:AgentImageUrlInMessageCreateMessage_Sync
+MessageImageUrlParam imageUrlParam = new MessageImageUrlParam(
+    url: "https://upload.wikimedia.org/wikipedia/commons/thumb/d/dd/Gfp-wisconsin-madison-the-nature-boardwalk.jpg/2560px-Gfp-wisconsin-madison-the-nature-boardwalk.jpg"
+);
+imageUrlParam.Detail = ImageDetailLevel.High;
+
+var contentBlocks = new List<MessageInputContentBlock>
+{
+    new MessageInputTextBlock("Could you describe this image?"),
+    new MessageInputImageUrlBlock(imageUrlParam)
+};
+
+client.CreateMessage(
+    threadId: thread.Id,
+    role: MessageRole.User,
+    contentBlocks: contentBlocks
+);
+```
+
+Asynchronous sample:
+```C# Snippet:AgentImageUrlInMessageCreateMessage
+MessageImageUrlParam imageUrlParam = new MessageImageUrlParam(
+    url: "https://upload.wikimedia.org/wikipedia/commons/thumb/d/dd/Gfp-wisconsin-madison-the-nature-boardwalk.jpg/2560px-Gfp-wisconsin-madison-the-nature-boardwalk.jpg"
+);
+imageUrlParam.Detail = ImageDetailLevel.High;
+var contentBlocks = new List<MessageInputContentBlock>
+{
+    new MessageInputTextBlock("Could you describe this image?"),
+    new MessageInputImageUrlBlock(imageUrlParam)
+};
+
+await client.CreateMessageAsync(
+    threadId: thread.Id,
+    role: MessageRole.User,
+    contentBlocks: contentBlocks
+);
+```
+
+5. Run the agent against the thread that now has an image to analyze.
+
+Synchronous sample:
+```C# Snippet:AgentImageUrlInMessageCreateRun_Sync
+ThreadRun run = client.CreateRun(
+    threadId: thread.Id,
+    assistantId: agent.Id
+);
+```
+
+Asynchronous sample:
+```C# Snippet:AgentImageUrlInMessageCreateRun
+ThreadRun run = await client.CreateRunAsync(
+    threadId: thread.Id,
+    assistantId: agent.Id
+);
+```
+
+6. Wait for the run to complete.
+
+Synchronous sample:
+```C# Snippet:AgentImageUrlInMessageWaitForRun_Sync
+do
+{
+    Thread.Sleep(TimeSpan.FromMilliseconds(500));
+    run = client.GetRun(thread.Id, run.Id);
+}
+while (run.Status == RunStatus.Queued
+    || run.Status == RunStatus.InProgress);
+```
+
+Asynchronous sample:
+```C# Snippet:AgentImageUrlInMessageWaitForRun
+do
+{
+    await Task.Delay(TimeSpan.FromMilliseconds(500));
+    run = await client.GetRunAsync(thread.Id, run.Id);
+}
+while (run.Status == RunStatus.Queued
+    || run.Status == RunStatus.InProgress);
+```
+
+7. Retrieve messages (including how the agent responds) and print their contents.
+
+Synchronous sample:
+```C# Snippet:AgentImageUrlInMessageReview_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:AgentImageUrlInMessageReview
+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;
+        }
+    }
+}
+```
+
+8. Finally, we delete all the resources, we have created in this sample.
+
+Synchronous sample:
+```C# Snippet:AgentImageUrlInMessageCleanup_Sync
+client.DeleteThread(thread.Id);
+client.DeleteAgent(agent.Id);
+```
+
+Asynchronous sample:
+```C# Snippet:AgentImageUrlInMessageCleanup
+await client.DeleteThreadAsync(thread.Id);
+await client.DeleteAgentAsync(agent.Id);
+```