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Core Web Vitals


Image Optimization for Largest Contentful Paint (LCP)

Does Image Optimization Affect Your LCP Score?

Saket Mittal
Largest Contentful Paint for Image Optimization

Have you ever experienced the frustration of seeing your website's rankings plummet on search engine result pages (SERPs), accompanied by a high bounce rate? You diligently created an enticing webpage, but your potential customers seem to leave within seconds of clicking on your link. The culprit behind this alarming trend? Slow loading of the above-the-fold content, especially images.

Slow-loading websites can quickly turn visitors away, diminishing rankings and missed opportunities. That's where Largest Contentful Paint (LCP) will help you identify which image is causing the issue. By optimizing your images, you can pinpoint and tackle the issues affecting your page loading speed head-on.

This blog will explore how image optimization for Largest Contentful Paint can revolutionize your website's user experience. Get ready to unlock the secrets to a lightning-fast and captivating online presence.

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Understanding Image Optimization for the Largest Contentful Paint

Image optimization is the process of reducing the file size of an image without significantly compromising its visual quality. It is achieved through various techniques such as compression, resizing, and format selection. When applied for the Largest Contentful Paint (LCP), it seeks to accelerate the loading time of the most significant content on a webpage. LCP is one of the core web vitals that measures the time it takes for the largest contentful element to become visible to users.

Since images often constitute a substantial portion of a webpage's content, they directly impact LCP.

An image that is too large requires more time to download, causing slower load times. It delays the rendering of the largest element on the screen, directly affecting LCP. A poor LCP score negatively affects user engagement and search engine rankings.

Optimizing images can greatly improve LCP and website performance. LCP image optimization involves specific techniques to improve the loading time of the largest visible image on a page. It includes reducing image file sizes, leveraging modern image formats like WebP or AVIF, implementing lazy loading to defer the loading of off-screen images, and using responsive image techniques to deliver appropriately sized images based on the user's device.

Benefits of Optimizing Images for LCP

1. It improves page loading speed, enhancing user experience and reducing bounce rates.

2. It helps reduce bandwidth usage and the amount of data transferred between servers and users' devices, especially for mobile users with limited data plans or slower internet connections.

LCP Image optimization carries similarities to typical image optimization. Both involve techniques like compression, lazy loading, and responsive design to ensure optimal image delivery. However, image optimization for LCP requires additional attention to detail, such as prioritizing loading the largest contentful images, using efficient image formats, and implementing caching strategies to reduce repeated downloads.

You may wonder if LCP image optimization only applies to certain websites or industries. The answer is no. Regardless of the website's nature, industry, or purpose, image optimization can benefit any website striving to improve its LCP and deliver a seamless user experience. Whether you operate an e-commerce platform, a news website, or a personal blog, optimizing your images for LCP is crucial.

Google recognizes the importance of image optimization for LCP and provides guidelines for website owners. According to Google, images should load within the first 2.5 seconds of a user accessing a page to achieve a good LCP score. Google recommends using formats like WebP or AVIF, compressing images without sacrificing quality, and employing lazy loading to improve LCP performance.

Image Optimization for LCP v/s FCP

FCP stands for First Contentful Paint, a performance metric that measures the time it takes for the first piece of content to be rendered on a web page. It indicates when the user can see something meaningful on the screen. FCP is a key metric for understanding the initial loading speed of a webpage.

LCP, on the other hand, measures the time for the largest element, such as an image or a block of text, to be rendered on the screen.

While FCP focuses on the first piece of content, LCP considers the largest element, meaning that FCP may not always represent the complete loading experience. LCP provides a better understanding of when the primary content becomes visible, offering a more comprehensive measure of perceived performance.

Image optimization plays a significant role in both FCP and LCP.

For FCP, reducing the file size and optimizing the loading of images can help improve the overall loading speed of the webpage. Since FCP measures the time it takes for the first piece of content to be rendered, optimizing images can contribute to a faster FCP by reducing the amount of data that needs to be downloaded and processed before the page becomes visible.

Similarly, for LCP, optimizing images becomes crucial as it measures the time it takes for the largest element to be rendered. If the image is not properly optimized, it can significantly slow down the LCP and impact the perceived performance of the website. By optimizing images, such as compressing them or using modern image formats, the load time of the largest element can be reduced, improving the LCP and overall user experience.

How to Optimize Images for LCP

You must follow a systematic approach to optimize images for improved Largest Contentful Paint (LCP). Implementing these steps allows you to enhance the loading speed of your website and provide a better user experience. Let's delve into each step in detail.

Identify Pages Facing LCP Issues

The first step is to identify the pages that experience slow loading due to images on both mobile and desktop devices. Tools like PageSpeed Insights and Lighthouse can provide detailed LCP reports, helping you pinpoint the problematic pages.

PageSpeed Insights offers a comprehensive analysis of your website's performance based on lab & field data. At the same time, Lighthouse is integrated into the Chrome Developer Tools and provides insights into various performance metrics based on lab data.

When using these tools, focus on indicators such as LCP score, loading time, and opportunities for improvement. Look for pages with significantly slower loading times compared to others. Additionally, differentiate between issues caused by images and other factors affecting page load times, such as server response time or JavaScript execution. It will help you understand whether images are the primary culprit or if there are other optimizations needed.

Prioritize the LCP Issues

Once you have identified the pages with slow image loading, it's essential to prioritize your image optimization efforts. Consider specific metrics or indicators to determine the priority. Factors like page importance, user traffic, and business goals can guide your decision-making. You might prioritize optimizing images on high-traffic pages to improve the user experience for a larger audience. Alternatively, focusing on images with the largest file sizes can significantly improve performance.

While tools like Lighthouse and PageSpeed Insights provide insights into which pages are causing specific issues, an advanced tool like Quattr can help you prioritize the issues based on their impact. Quattr comprehensively analyzes all your web pages simultaneously, allowing you to identify the most impacted pages based on LCP scores and allocate your optimization efforts accordingly.

Perform Image Optimization for LCP

Optimizing images for improved LCP requires implementing practices focusing on reducing image file sizes and enhancing loading speed. Here are the advanced practices your should follow:

1. Image Compression: Compress images using appropriate tools and techniques to reduce file sizes without compromising quality. Implement formats such as WebP or JPEG 2000 for better compression efficiency.

2. Lazy Loading: Utilize lazy loading techniques to defer the loading of images not initially visible on the screen. It reduces the initial loading time and prioritizes the loading of critical images.

3. Responsive Images: Implement responsive image techniques to deliver appropriately sized images based on the user's device and screen size. Serve different versions of images to different devices, ensuring optimal loading speed.

4. Image Caching: Leverage browser caching to store images on the user's device, allowing for faster subsequent visits. Set appropriate cache-control headers to control how long the images are stored.

5. CDN Implementation: Utilize a Content Delivery Network (CDN) to distribute your images across multiple servers, improving delivery speed and reducing latency.

Measuring & Monitoring Image Performance for LCP

Measuring and monitoring image performance for LCP is crucial to ensure a consistently fast website. Regular monitoring allows you to identify new performance issues and make necessary improvements. The frequency of monitoring depends on the size and complexity of your website, but monitoring performance regularly, such as monthly or quarterly, is recommended.

Track metrics like LCP score, loading time, and image-specific metrics like image size and compression ratio. Monitoring these metrics allows you to assess the effectiveness of your image optimization efforts and identify areas for further improvement.

Several tools can help in measuring image performance. One such tool is Quattr, which provides advanced insights and analysis of your website's performance, including LCP optimization. Quattr offers a user-friendly interface, comprehensive reports, and real-time monitoring capabilities, making it an ideal tool for measuring and improving image performance for LCP. You can gain in-depth visibility into your website's image optimization, compare performance across different pages, and make data-driven decisions to enhance the overall website performance.

Common Mistakes to Avoid in LCP Image Optimization

Achieving optimal performance in LCP image optimization requires a keen understanding of the potential pitfalls hindering your efforts. By avoiding these common mistakes, you can ensure that your website delivers fast loading times and an exceptional user experience. Here are some common mistakes to avoid when optimizing images for LCP:

1. Missing Alt Text and Poor File Naming: Without relevant alt text and descriptive file names, search engines might struggle to understand the context of your images. It can negatively impact your SEO rankings. Use meaningful file names and incorporate relevant keywords in your alt text for better accessibility & optimization.

Use our Alt text generator tool to get SEO-friendly alt text recommendations for your images.

2. Overlooking Image Dimensions: Uploading images larger than the required size slows the page load time, affecting the LCP. Images should be resized according to the maximum display size on your website to enhance page speed.

3. Ignoring Next-Gen Image Formats: Using outdated image formats like JPEG or PNG can detriment your LCP image optimization efforts. Next-generation formats like JPEG 2000, JPEG XR, and WebP provide superior compression and quality characteristics, significantly reducing load time and improving the LCP score.

4. Overuse of Heavy, Non-Optimized Images: Using excessively heavy, non-optimized images takes longer to load and can significantly slow the website. It's crucial to balance the number and quality of images used on a page for optimal performance.

5. Disregarding Browser Caching Settings: Not leveraging browser caching settings forces your users' browsers to load the entire webpage from scratch every time they visit, naturally slowing down the loading. Configure your cache settings to ensure commonly used files are saved in the user's browser, providing a quicker load time on subsequent visits.

Keep Optimizing Images for Improved LCP

Optimizing images for LCP is critical to website performance and user experience. By understanding the importance of LCP, implementing advanced image optimization techniques, and avoiding common mistakes, you can significantly improve user engagement and increase search engine rankings, leading to increased visibility and organic traffic.

As technology and user expectations evolve, regular performance audits staying updated with the latest image optimization techniques, tools, and best practices is essential. It helps you detect performance issues before they significantly impact user experience and search engine rankings. Regularly monitoring and analyzing image performance, utilizing tools like Quattr, will help you identify areas for improvement and make informed decisions to optimize your website's LCP further.

Remember, effective image optimization for LCP is an ongoing process that requires continuous refinement and adaptation. Prioritizing these optimization allows you to provide a lightning-fast browsing experience, engage your audience, and stay ahead in the competitive online landscape.

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LCP Image Optimization FAQs

Is it better to use CSS backgrounds or HTML images for LCP optimization?

LCP image optimization using CSS backgrounds or HTML images depends on various factors. CSS backgrounds offer flexibility and can be optimized through lazy loading and responsive design. HTML images, on the other hand, provide better accessibility and SEO benefits. Consider the specific requirements of your website and choose the approach that best aligns with your goals for LCP image optimization.

What should you do if your LCP is still slow after image optimization?

If your Largest Contentful Paint (LCP) is still slow after image optimization, consider further optimizing your HTML and CSS code, leveraging browser caching and preloading techniques, reducing server response time, and evaluating the impact of third-party scripts on page load speed.

Can image optimization alone improve LCP significantly?

While image optimization is crucial in improving LCP, it is not the sole factor that can significantly impact it. Other elements, such as server response times, render-blocking resources, and overall page structure, also contribute to LCP performance. To achieve significant improvements, it's important to take a holistic approach by optimizing various aspects of your website, including images, CSS, JavaScript, and server configurations.

Are there any limitations to using modern image formats like WebP?

Modern image formats like WebP offer numerous benefits, such as smaller file sizes and transparency support but they have limitations. WebP has limited browser support, as older browsers may not be compatible with WebP. It may not be suitable for all types of images, particularly those with complex gradients or fine details, as it may result in a loss of image quality.

About The Author

Saket Mittal

Saket Mittal is a Marketing Analyst at Quattr and helps drive traffic to the website by improving user experience. He is a an expert Quattr platform user and takes charge in improving product experience and conversions. Saket writes about content marketing, website optimization, and expert tips on how to use Google Search Console for content SEO.

About Quattr

Quattr is an innovative and fast-growing venture-backed company based in Palo Alto, California USA. We are a Delaware corporation that has raised over $7M in venture capital. Quattr's AI-first platform evaluates like search engines to find opportunities across content, experience, and discoverability. A team of growth concierge analyze your data and recommends the top improvements to make for faster organic traffic growth. Growth-driven brands trust Quattr and are seeing sustained traffic growth.

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