In today’s competitive digital landscape, website performance is more important than ever. Google’s Core Web Vitals are a key set of metrics that measure how fast and responsive your website is — and they directly impact both SEO rankings and user experience.
For HubSpot users, one of the most common issues affecting Core Web Vitals is large, unoptimized images. Images often make up the largest portion of a webpage’s total size, so poor image management can lead to slow load times, delayed interactions, and layout shifts — all of which can hurt your Core Web Vitals score.
In this article, we’ll break down how image optimization can improve your Core Web Vitals and help your HubSpot site perform better in search rankings and user engagement.
Core Web Vitals are a set of three performance metrics introduced by Google to measure the quality of a website’s user experience. These include:
LCP measures how long it takes for the largest visible content (like an image or hero section) to load. A good LCP score is under 2.5 seconds.
FID measures how long it takes for the site to respond to a user’s first interaction (like clicking a button). A good FID score is under 100 milliseconds.
CLS measures how much the page layout shifts while loading. A good CLS score is under 0.1.
Images are often the largest files on a webpage, and unoptimized images can negatively affect all three Core Web Vitals:
Large image files are often the largest elements on a page. Reducing file size through compression allows images to load faster. Faster loading = better LCP scores.
Example: A 2 MB image reduced to 200 KB can reduce LCP time by up to 80%.
If images load slowly or resize as they load, they can push content around and create a poor user experience. Setting correct width and height attributes ensures that the browser knows the image size before it loads. This reduces unexpected layout shifts and improves CLS.
Best Practice: Define the width and height of all images directly in the HTML or CSS.
Heavy pages caused by large images can delay browser responsiveness. Reducing file size and total page weight allows the browser to respond more quickly to user input. Lighter pages = faster interaction = better FID.
Example: Reducing total page size from 5 MB to 1 MB can reduce FID time significantly.
If you're using HubSpot, following these best practices can help improve your Core Web Vitals:
Use modern compression techniques to reduce image file size without compromising visual quality. Consider both lossless (preserves detail) and lossy (more aggressive compression) methods depending on your needs.
WebP images are typically 25% to 35% smaller than PNG and JPEG files with no noticeable quality loss. Most modern browsers (including Chrome and Edge) support WebP.
Lazy loading defers the loading of offscreen images until the user scrolls down to them. This reduces initial page load size and improves LCP.
Example: Use the loading="lazy" attribute for images in your HTML.
Use responsive design techniques to serve appropriately sized images for desktop, tablet, and mobile views. Consider using srcset to provide multiple versions of an image for different devices.
For critical images (like hero banners), use rel="preload" in the HTML <head> to load them sooner. This tells the browser to prioritize loading these images.
Example:
<link rel="preload" as="image" href="/path-to-image.jpg">
Instead of manually compressing and resizing images, tools like Pixel Compress can automate the entire process. Pixel Compress works directly with HubSpot, compressing images as you upload them — behind the scenes — to ensure they are optimized for the best possible performance without any extra effort.
By automating image compression, Pixel Compress helps you maintain fast load times and better Core Web Vitals without sacrificing quality.
Improving Core Web Vitals leads to:
Optimizing images for HubSpot is one of the simplest and most effective ways to improve your Core Web Vitals. Faster loading times, fewer layout shifts, and quicker interactions lead to better search rankings and a smoother user experience.
By following the best practices above and using modern compression techniques — or automating the process with a tool like Pixel Compress — you can significantly boost your site’s performance and search visibility.