This is the default for <div> elements but should be specified otherwise.
Examples
Responsive
 import Image from 'next/image'
import mountains from '../public/mountains.jpg'
 
export default function Responsive() {
  return (
    <div style={{ display: 'flex', flexDirection: 'column' }}>
      <Image
        alt="Mountains"
        // Importing an image will
        // automatically set the width and height
        src={mountains}
        sizes="100vw"
        // Make the image display full width
        style={{
          width: '100%',
          height: 'auto',
        }}
      />
    </div>
  )
}
Fill Container
 import Image from 'next/image'
import mountains from '../public/mountains.jpg'
 
export default function Fill() {
  return (
    <div
      style={{