---
title: Images in Next.js
date: '2020-11-11'
tags: ['next js', 'guide']
draft: true
summary: 'In this article we introduce adding images in the tailwind starter blog and the benefits and limitations of the next/image component.'
---

# Introduction

The tailwind starter blog has out of the box support for [Next.js's built-in image component](https://nextjs.org/docs/api-reference/next/image) and automatically swaps out default image tags in markdown or mdx documents to use the Image component provided.

# Usage

To use in a new page route / javascript file, simply import the image component and call it e.g.

```js
import Image from 'next/image'

function Home() {
  return (
    <>
      <h1>My Homepage</h1>
      <Image src="/me.png" alt="Picture of the author" width={500} height={500} />
      <p>Welcome to my homepage!</p>
    </>
  )
}

export default Home
```

For a markdown file, the default image tag can be used and the default `img` tag gets replaced by the `Image` component in the build process.

Assuming we have a file called `logo.png` in `static/images/logo.png`, the following line of code would generate the optimized image.

```
![logo](static/images/logo.png)
```

Alternatively, since we are using mdx, we can just use the image component directly! Note, that you would have to provide a fixed width and height. The `img` tag method parses the dimension automatically.

```js
<Image alt="ocean" src="/static/images/logo.png" width={256} height={128} />
```

_Note_: If you try to save the image, it is in webp format, if your browser supports it!

![logo](/static/images/logo.png)

# Benefits

- Smaller image size with Webp (~30% smaller than jpeg)
- Responsive images - the correct image size is served based on the user's viewport
- Lazy loading - images load as they are scrolled to the viewport
- Avoids [Cumulative Layout Shift](https://web.dev/cls/)
- Optimization on demand instead of build-time - no increase in build time!

# Limitations

- Due to the reliance on `next/image`, unless you are using an external image CDN like Cloudinary or Imgix, it is practically required to use Vercel for hosting. This is because the component acts like a serverless function that calls a highly optimized image CDN.

  If you do not want to be tied to Vercel, you can remove `imgToJsx` in `remarkPlugins` in `lib/mdx.js`. This would avoid substituting the default `img` tag.

  Alternatively, one could wait for image optimization at build time to be supported. A different library, [next-optimized-images](https://github.com/cyrilwanner/next-optimized-images) does that, although it requires transforming the images through webpack which is not done here.

- Images from external links are not passed through `next/image`
- All images have to be stored in the `public` folder e.g `/static/images/logo.png`
