Add hosting integration section to text-to-image quickstart

[Copilot]

Summary

Adds documentation showing how to use AddAzureOpenAIClient and AddImageGenerator with dependency injection in hosted applications, addressing feedback from the text-to-image article review.

Fixes #49391 (discussion thread)

Changes

• New section: "Use hosting integration" added before "Best practices"

  • Shows Aspire.Azure.AI.OpenAI package usage for registering Azure OpenAI client
  • Demonstrates AddImageGenerator for DI container registration
  • Includes minimal API endpoint example with IImageGenerator injection

• Code sample: Complete ASP.NET Core web app at snippets/text-to-image/hosting/TextToImageHosting/

  • Uses connection string from configuration for Azure OpenAI endpoint
  • Registers image generator as singleton service
  • Example POST endpoint returning generated image as response

Example Usage

var openai = builder.AddAzureOpenAIClient("openai");

builder.Services.AddImageGenerator(services =>
{
    var openAiClient = services.GetRequiredService<OpenAIClient>();
    return openAiClient.GetImageClient("gpt-image-1").AsIImageGenerator();
});

app.MapPost("/generate-image", async (IImageGenerator generator, string prompt) =>
{
    var response = await generator.GenerateImagesAsync(prompt, new ImageGenerationOptions());
    return Results.File(response.Contents.OfType<DataContent>().First().Data.ToArray(), "image/png");
});

Follows pattern from ericstj/imageGeneratorSample.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Show how to use hosting for AddAzureOpenAIClient and AddImageGenerator</issue_title>
<issue_description>Add a section to the end of the https://github.com/dotnet/docs/blob/main/docs/ai/quickstarts/text-to-image.md article that shows how to use this stuff with hosting, by using things like AddAzureOpenAIClient and AddImageGenerator (similar to https://github.com/ericstj/imageGeneratorSample/blob/8a976997f5a762885c2fa3e76c206723263c3ded/imageGeneratorSample.Web/Program.cs#L16-L26.)

Originally posted by @ericstj in #49391 (comment)
</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Show how to use hosting for AddAzureOpenAIClient and AddImageGenerator #49445

---

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Internal previews

📄 File	🔗 Preview link
docs/ai/quickstarts/text-to-image.md	Generate images from text using AI

[Copilot]

Pull Request Overview

This PR adds a new "Use hosting integration" section to the text-to-image quickstart documentation, demonstrating how to integrate image generation capabilities into ASP.NET Core applications using dependency injection and the Aspire Azure OpenAI package. The addition addresses feedback from the original article review and follows the pattern established in a reference sample repository.

• Adds comprehensive hosting integration documentation showing dependency injection setup with AddAzureOpenAIClient and AddImageGenerator
• Includes a complete working ASP.NET Core web application sample demonstrating the hosting pattern
• Documents configuration management through connection strings and the benefits of the DI approach

Reviewed Changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 12 comments.

Show a summary per file

File	Description
docs/ai/quickstarts/text-to-image.md	Adds "Use hosting integration" section with setup instructions, code examples, and benefits explanation
docs/ai/quickstarts/snippets/text-to-image/hosting/TextToImageHosting/Program.cs	Complete ASP.NET Core sample demonstrating Azure OpenAI client registration and image generator endpoint
docs/ai/quickstarts/snippets/text-to-image/hosting/TextToImageHosting/TextToImageHosting.csproj	Project file with required NuGet packages for hosting integration
docs/ai/quickstarts/snippets/text-to-image/hosting/TextToImageHosting/appsettings.json	Configuration file showing connection string structure for Azure OpenAI
docs/ai/quickstarts/snippets/text-to-image/hosting/TextToImageHosting/appsettings.Development.json	Development-specific logging configuration
docs/ai/quickstarts/snippets/text-to-image/hosting/TextToImageHosting/Properties/launchSettings.json	Launch profiles for HTTP and HTTPS debugging

[BillWagner]

This LGTM @gewarren

You can decide how to handle the Copilot feedback. Some of it seems reasonable.

[gewarren]

@ericstj This is a preview of the new section on hosting. Can you look it over?

[ericstj]

We could set these up with ConfigureOptions on the builder if we wanted to demonstrate that API.

[ericstj]

Do we want to include UseLogging or ConfigureOptions

[ericstj]

We could further improve this if Aspire adds support like AddChatClient and we add an OpenTelemetryImageGenerator. Not sure if that's important for folks usage though.

[ericstj]

Looks good in general, just a couple small suggestions to demonstrate additional API.