Story Based Question
You’re managing a news website with thousands of articles and images. You notice that some pages are loading slower than others, and after investigating, you discover that some of your images don’t have properly set dimensions. These images are being stretched or squished, leading to delays in rendering. You’re wondering: How important is it to set proper dimensions for images, and how does this affect your website’s performance?
Exact Answer
Setting proper dimensions for images ensures they load faster, display correctly, and prevent layout shifts. This improves page load speed, user experience, and SEO performance by reducing unnecessary reflows and repaints during page rendering.
Explanation
Setting proper dimensions for your images is critical for both performance and user experience. When images don’t have fixed width and height values, browsers are forced to calculate the image dimensions during page load, which can delay the rendering process. This delay leads to layout shifts, where content moves around as images load, which negatively impacts the user experience.
When you set the correct dimensions for your images, you provide the browser with the information it needs to reserve the right amount of space for the image before it fully loads. This prevents layout shifts and ensures that your page doesn’t jump around as the images appear. It’s an essential factor in improving Core Web Vitals, particularly the Cumulative Layout Shift (CLS) metric, which directly affects your SEO ranking.
Additionally, specifying image dimensions helps the browser allocate the necessary resources in advance, so it doesn’t waste time adjusting the page layout. This optimizes page load speed and prevents the browser from needing to reflow or repaint the page, which can cause lag.
Properly set image dimensions also ensure that the images don’t appear distorted. If an image is stretched or squished because it lacks dimensions, it will either look pixelated or out of place. By providing proper dimensions, you ensure the images look crisp and correctly proportioned across all devices, maintaining a polished and professional look for your site.
Furthermore, setting fixed dimensions for images helps with responsive design. On mobile devices, for example, setting the correct dimensions ensures that images are displayed in the right aspect ratio without stretching or cropping, contributing to a smoother user experience.
Example
Let’s say you run a news website and feature large images in your articles. Some images, however, don’t have proper width and height attributes set, leading to problems:
- When a user opens an article, they experience a layout shift as the images load, causing the page to jump around.
- This results in a poor user experience, especially on mobile, where the layout shifts are more noticeable.
- The images appear either squished or stretched, causing distortion and an unprofessional look.
Now, you decide to set the proper dimensions for each image:
- For example, you set the width to 800px and height to 600px for images within article text.
- The browser knows exactly how much space to reserve for each image, preventing any layout shifts.
- The images load in their correct aspect ratio, appearing crisp and proportionate across devices.
The result:
- Page load times improve because the browser doesn’t need to calculate the image’s dimensions.
- User experience enhances, as the images display correctly, and the layout stays intact without shifts.
- Your site’s SEO improves, as the Cumulative Layout Shift (CLS) metric decreases, leading to better rankings in search engines.
Setting proper dimensions for images is a small but crucial detail in ensuring fast load times, correct layout rendering, and a seamless user experience. It plays a significant role in Core Web Vitals, particularly for reducing layout shifts and improving SEO. By taking the time to specify image dimensions, you help your pages load smoothly, look professional, and rank better on search engines.