minimumCacheTTL
You can configure the Time to Live (TTL) in seconds for cached optimized images. In many cases, it's better to use a Static Image Import which will automatically hash the file contents and cache the image forever with a Cache-Control header of immutable.
next.config.js module.exports = {
  images: {
    minimumCacheTTL: 60,
  },
}
The expiration (or rather Max Age) of the optimized image is defined by either the minimumCacheTTL or the upstream image Cache-Control header, whichever is larger.
If you need to change the caching behavior per image, you can configure headers to set the Cache-Control header on the upstream image (e.g. /some-asset.jpg, not /_next/image itself).