Question
Answer and Explanation
Using Retina (2x) images in CSS easily involves a few techniques that ensure high-resolution displays render images sharply without pixelation. Here are some straightforward approaches:
1. Using CSS Background-Size Property:
- This is a very common method. Prepare two versions of your image: a regular one (e.g., `image.png`) and a Retina version with twice the resolution (e.g., `image@2x.png`).
- In your CSS, you’ll specify the `background-image` with the regular image, and then use `background-size` to scale the image down to the appropriate size.
.my-element {
background-image: url("image.png");
background-size: 100px 50px; / Adjust dimensions accordingly /
}
@media (-webkit-min-device-pixel-ratio: 2),
(min-resolution: 192dpi) {
.my-element {
background-image: url("image@2x.png");
}
}
- The `@media` query targets devices with at least twice the pixel density.
- Make sure `image@2x.png` is exactly double the size of `image.png` to avoid distortion or bluring.
2. Using the <picture> element (for Images):
- The HTML5 <picture> element allows you to specify different sources based on screen properties. However this will use img instead of a background.
<picture>
<source srcset="image.png" media="(max-resolution: 191dpi)">
<source srcset="image@2x.png" media="(min-resolution: 192dpi)">
<img src="image.png" alt="My Image">
</picture>
- This allows browsers to pick the correct image, making sure that low and high resolution images load properly on their respective screen types.
3. Using CSS Image-set:
- The CSS image-set property allows you to specify images that the browser should choose from based on pixel density (not available for older browsers).
.my-element {
background-image: image-set(
url("image.png") 1x,
url("image@2x.png") 2x
);
background-size: 100px 50px;
}
- In this method, the 1x and 2x refer to the image’s pixel ratio.
4. Using an Img element:
- If you don't want to use a background, a more direct aproach can also be used via img element.
<img srcset="image.png 1x, image@2x.png 2x" src="image.png" alt="My Image" />
- As with `image-set`, the `1x` and `2x` specifies the intended pixel density.
Additional Tips:
- For large images it's recommned to optimize them using services like imageOptim.
- Use file names that make it easy to identify 1x and 2x images (eg. name@2x.png)
- When scaling with `background-size`, use precise dimensions to prevent blur.
By implementing any of these methods you can use high res images for your webpage!