I want to deliver the lighter image as possible for my website. To accomplish that, usually use source with that sort of HTML code :

<picture>
    <source
      srcset="assets/images/compressed/litopia-s4-256.avif"
      media="(max-width: 512px)"
      type="image/avif"
    />
    <source
      srcset="assets/images/compressed/litopia-s4-512.avif"
      media="(max-width: 1024px)"
      type="image/avif"
    />
    <source
      srcset="assets/images/compressed/litopia-s4-1024.avif"
      media="(max-width: 2048px)"
      type="image/avif"
    />
    <!-- webp -->
    <source
      srcset="assets/images/compressed/litopia-s4-256.webp"
      media="(max-width: 512px)"
      type="image/webp"
    />
    <source
      srcset="assets/images/compressed/litopia-s4-512.webp"
      media="(max-width: 1024px)"
      type="image/webp"
    />
    <source
      srcset="assets/images/compressed/litopia-s4-1024.webp"
      media="(max-width: 2048px)"
      type="image/webp"
    />
    <!-- jpeg -->
    <source
      srcset="assets/images/compressed/litopia-s4-256.jpg"
      media="(max-width: 512px)"
      type="image/jpeg"
    />
    <source
      srcset="assets/images/compressed/litopia-s4-512.jpg"
      media="(max-width: 1024px)"
      type="image/jpeg"
    />
    <source
      srcset="assets/images/compressed/litopia-s4-1024.jpg"
      media="(max-width: 2048px)"
      type="image/jpeg"
    />
    <img src="/assets/images/litopia-port-s4.png" alt="Litopia Season 4">
</picture>

And I would like to know if there is something similar when I intend to deliver an image using background-image in CSS

like this :

.bg-img{
  background-image: url("/assets/images/litopia-s4.png");
  background-size:cover;
}

CodePudding user response：

You can definitely do that with media queries :

@media (max-width: 1024px) {
  .bg-img{
     background-image: url("/assets/images/litopia-s4-512.png");
     background-size:cover;
  }
}
@media (max-width: 512px) {
  .bg-img{
     background-image: url("/assets/images/litopia-s4-256.png");
     background-size:cover;
  }
}

Pay attention to the sequential order of Media Queries : it matters. (from the highest to lowest resolution)

Edit

Didn't see @Kaiido comment before posting. But yeah, to check if your media format is handle, Modernizr would be the way to go I think.