


How do I use the poster attribute to display a preview image before the video starts playing?
Jun 22, 2025 am 12:46 AMThe poster attribute is used in HTML5 to specify the preview image displayed before the video starts playing, which is achieved by adding an image URL to the
The poster
attribute in HTML5 is used to specify an image that will be displayed before the video starts playing. It's a simple but useful feature for giving users a visual preview of the video content. You just need to provide a URL to an image file, and it'll show up until the user hits play.
Here's how to use it effectively:
How to Add the Poster Attribute
To display a preview image, all you need is an <img src="/static/imghw/default1.png" data-src="video.mp4" class="lazy" alt="How do I use the poster attribute to display a preview image before the video starts playing?" >
-like URL inside your <video></video>
tag:
<video controls poster="preview.jpg"> <source type="video/mp4"> Your browser does not support the video tag. </video>
Make sure the image path is correct, and the file exists where you say it does. Otherwise, the browser might show nothing or a broken image icon.
Choosing the Right Image
It's not just about adding any image — the right one can improve user experience and encourage engagement. Here are a few tips:
- Use a high-quality screenshot from the video itself (ideally a key frame).
- Avoid overly dark or blurry frames that don't represent the content well.
- Consider adding subtle text like “Click to Play” if it doesn't distract.
- Optimize the image size for fast loading — no need for ultra-high-res.
If you're working on a site with many videos, it's a good idea to have a consistent style for your poster images.
When the Poster Might Not Show Up
There are a few common reasons why your poster image might not appear:
- The
poster
URL is incorrect or points to a missing image. - Some browsers may ignore the poster if the video loads too quickly.
- If JavaScript dynamically adds the
src
, the poster may not behave as expected unless handled properly.
Also, some mobile browsers might not display the poster until the user interacts with the page due to autoplay restrictions.
Responsive Posters and Styling Tips
You don't need extra code for the poster to scale — it should fill the video element by default. But if you want more control, consider these tweaks:
- Wrap the video in a container and use CSS to adjust the poster appearance.
- Use
object-fit: cover
orcontain
if you want specific scaling behavior. - On smaller screens, you might want to switch to a different poster image using media queries — though this usually requires JavaScript or server-side logic.
Keep in mind that styling the poster directly isn't always possible since it's rendered inside the video element.
Basically that's it. As long as the path is correct and the picture is appropriate, it is easy to use poster
well, but details are easily overlooked.
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