feat(langchain): add support for image generation tool

[christian-bromann]

Add Image Generation Tool for OpenAI Responses API

Summary

This PR adds a new imageGeneration tool for the OpenAI provider, enabling models to generate and edit images using text prompts via the Responses API.

Usage

import { ChatOpenAI, tools } from "@langchain/openai";

const model = new ChatOpenAI({ model: "gpt-4o" });

const response = await model.invoke(
  "Generate an image of a sunset over mountains",
  {
    tools: [tools.imageGeneration({
      size: "1536x1024",
      quality: "high",
      outputFormat: "jpeg",
    })]
  }
);

Supported Models

gpt-4o, gpt-4o-mini, gpt-4.1, gpt-4.1-mini, gpt-4.1-nano, o3

[changeset-bot]

🦋 Changeset detected

Latest commit: 5bc2c23

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 5 packages

Name	Type
@langchain/openai	Minor
@langchain/classic	Patch
@langchain/community	Patch
@langchain/deepseek	Patch
@langchain/xai	Patch

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