Solving the Mysterious Case of the Broken Image: Image Working on Localhost but Broken in Production in Next.js

If you’re reading this, chances are you’re stuck in a frustrating situation where your images are working perfectly fine on localhost, but suddenly break when you deploy your Next.js application to production. Don’t worry, you’re not alone! This article is here to guide you through the troubleshooting process and provide a comprehensive solution to this common issue.

The Investigation Begins

To understand what’s going on, let’s dive into the basics of how Next.js handles images. When you run your application in development mode (localhost), Next.js uses a built-in development server that serves files from the `public` folder. This means that any images you place in the `public` folder will be served directly by the development server, and thus will work as expected.

However, when you deploy your application to production, the story changes. Next.js uses a different approach to serve static assets, including images. By default, Next.js uses the `static` export in `next.config.js` to serve static files from a CDN or a cloud storage service like AWS S3. This is where the issue arises, as the image URLs are not correctly configured, leading to broken images in production.

Gathering Clues: Common Reasons for Broken Images

Before we dive into the solutions, let’s explore some common reasons why images might break in production:

• Incorrect Image URLs: If your image URLs are hardcoded or relative, they might not work in production, leading to broken images.
• Misconfigured `next.config.js`: Incorrect or missing configuration in `next.config.js` can cause issues with image serving.
• Missing or Incorrect `public` Folder Configuration: If the `public` folder is not configured correctly, images might not be served correctly in production.
• CDN or Cloud Storage Misconfiguration: Issues with CDN or cloud storage configuration can lead to broken images in production.

Solving the Mystery: Step-by-Step Solutions

Now that we’ve explored the common reasons behind broken images, let’s dive into the step-by-step solutions to fix this issue:

Step 1: Use Absolute URLs for Images

To ensure that image URLs work correctly in production, use absolute URLs instead of relative or hardcoded URLs. Update your image tags to use the following format:

<img src={`${process.env.BASE_URL}/image.jpg`} />

Here, `process.env.BASE_URL` will be replaced with the correct base URL for your production environment.

Step 2: Configure `next.config.js` Correctly

Make sure your `next.config.js` file is configured correctly to serve static files, including images. Add the following configuration to your `next.config.js` file:

module.exports = {
  //... other configurations ...
  asset: {
    publicPath: '/static/',
  },
  exportPathMap: async () => {
    return {
      '/': { page: '/' },
      '/static/*': { page: '/static/[slug]' },
    };
  },
};

This configuration tells Next.js to serve static files from the `public` folder and use the `/static/` path for images and other assets.

Step 3: Configure the `public` Folder Correctly

Ensure that the `public` folder is configured correctly in your Next.js project. Create a `next.config.js` file with the following configuration:

module.exports = {
  //... other configurations ...
  publicRuntimeConfig: {
    staticFolder: './public',
  },
};

This configuration tells Next.js to use the `public` folder for static assets.

Step 4: Verify CDN or Cloud Storage Configuration

If you’re using a CDN or cloud storage service like AWS S3, ensure that the configuration is correct and the images are accessible via the correct URL. Verify that the images are uploaded to the correct location and the CDN or cloud storage service is properly configured.

The Grand Finale: Putting it All Together

Now that we’ve covered the individual steps to solve the mystery of the broken image, let’s put it all together:

Here’s an example of a Next.js project with the correct configuration:

// next.config.js
module.exports = {
  asset: {
    publicPath: '/static/',
  },
  exportPathMap: async () => {
    return {
      '/': { page: '/' },
      '/static/*': { page: '/static/[slug]' },
    };
  },
  publicRuntimeConfig: {
    staticFolder: './public',
  },
};

// pages/_app.js
import Head from 'next/head';

function MyApp({ Component, pageProps }) {
  return (
    <>
      <Head>
        <link rel="icon" href={`${process.env.BASE_URL}/favicon.ico`} />
      </Head>
      <Component {...pageProps} />
    <}>
  );
}

export default MyApp;

// components/Image.js
import React from 'react';

const Image = ({ src, alt }) => {
  return <img src={`${process.env.BASE_URL}/${src}`} alt={alt} />;
};

export default Image;

// public/index.html
<html>
  <head>
    <title>My Next.js App</title>
  </head>
  <body>
    <img src="/static/image.jpg" alt="My Image" />
  </body>
</html>

In this example, we’ve configured `next.config.js` to serve static files, including images, from the `public` folder. We’ve also updated the image URLs to use absolute URLs and configured the `public` folder correctly.

Conclusion

Solving the mystery of the broken image in Next.js production is a matter of understanding how Next.js handles images and configuring the project correctly. By following the steps outlined in this article, you should be able to resolve the issue and ensure that your images are working correctly in production.

Remember to always use absolute URLs for images, configure `next.config.js` correctly, and verify your CDN or cloud storage configuration. With these steps, you’ll be well on your way to solving the mystery of the broken image and deploying a successful Next.js application.

Summary of Solutions
Use absolute URLs for images
Configure `next.config.js` correctly
Configure the `public` folder correctly
Verify CDN or cloud storage configuration

By following these solutions, you’ll be able to resolve the issue of images working on localhost but breaking in production, and ensure a successful deployment of your Next.js application.

Additional Resources

If you’re still having trouble with broken images in production, here are some additional resources to help you troubleshoot the issue:

• Next.js `next.config.js` documentation
• Next.js `publicRuntimeConfig` documentation
• Stack Overflow: Images not loading in Next.js production mode

I hope this article has helped you solve the mystery of the broken image in Next.js production. Happy coding!

Frequently Asked Question

Having trouble with your Next.js app? Don’t worry, we’ve got you covered! Check out these frequently asked questions to troubleshoot your image issues.