How Image Optimization Boosts Speed, SEO, and User Experience: What You’re Overlooking
Let’s talk about something fundamental yet often overlooked in website optimization: images. You know, those beautiful high-res photos that make your website stand out—but also drag it down. You’ve probably heard the phrase “a picture is worth a thousand words,” but what they don't tell you is that a poorly optimized picture can cost you thousands in lost traffic and conversions.
Today, we’re diving deep into what makes image optimization critical for your website’s performance and what Google has to say about it. I’ll walk you through some pro tips from Google’s own Martin Splitt, and we’ll cover the latest scoop on AVIF—a game-changing image format you’ll want to know about.
Why Images Matter (and Why They’re a Double-Edged Sword)
Images aren’t just eye candy. They set the tone for your site and help shape that all-important first impression. But let’s be real—while images are great, they come with a cost. Heavy, unoptimized images slow down your site, frustrate users, and mess with your SEO.
Now, you might be thinking, “So, what can I do about it?” That’s where things get interesting. Martin Splitt, Search Relations Advocate from Google, recently laid out some solid tips on how to optimize images for the web, without compromising on quality. Let’s break it down.
Tip #1: Choose the Right Image Format
This isn’t just about choosing between JPEG, PNG, and GIF anymore. Sure, those are the classics, but today, we’ve got newer players like WebP and AVIF, which bring serious performance benefits to the table.
WebP and AVIF are the future of web images. WebP offers better compression than JPEG without much loss in quality. But AVIF? That’s next-level stuff. It’s based on the AV1 video compression standard and offers insanely efficient file sizes while maintaining top-notch quality.
Pro tip: Don’t blindly convert all your images to these new formats. Use tools like Squoosh to compare different formats, and see what works best for your site’s specific needs.
Tip #2: Compress, Compress, Compress
We’ve all been there. You’re uploading a beautiful, crisp image and you want to keep all that glorious detail—but at what cost?
Here’s the golden rule: Compress images as much as possible without losing more quality than you’re comfortable with. Automation can help with this, but a hands-on approach might be needed for key images where the detail really matters. Tools like TinyPNG or Squoosh can help you squeeze those file sizes down without making your images look like they’ve been run through a blender.
Tip #3: Responsive Sizing for the Win
Have you ever noticed that a picture on your phone looks great, but then you blow it up on a desktop and, well… not so much? Here’s a strategy to tackle that issue: responsive image sizing.
The key here is to serve smaller, compressed images to mobile users while sending higher-quality images to desktop visitors. This keeps your site fast for everyone. You can do this using the <picture> element or the srcset attribute in HTML, both of which tell the browser which image version to serve based on the user’s device.
Here’s the cherry on top: Google Search will also use your fallback image if needed, which means you’re covered on all fronts. Add some structured data, and you’re golden.
Tip #4: Lazy Load Like a Pro
Finally, let’s talk about lazy loading—one of the simplest ways to shave seconds off your page load time. Instead of loading every image on your page right off the bat, lazy loading defers non-essential images until they’re needed, like when a user scrolls down.
But here’s a warning: Don’t go overboard. You don’t want to lazy-load everything, especially images that are immediately visible. Conveniently, modern browsers support this through the loading attribute in HTML. Just pop in loading="lazy" on your images, and you’re good to go.
Example of HTML code demonstrating responsive image loading and lazy loading for the same image:
<picture>
<source srcset="image-small.avif 480w, image-medium.avif 800w, image-large.avif 1200w" type="image/avif">
<source srcset="image-small.webp 480w, image-medium.webp 800w, image-large.webp 1200w" type="image/webp">
<img src="image.jpg" srcset="image-small.jpg 480w, image-medium.jpg 800w, image-large.jpg 1200w" sizes="(max-width: 600px) 480px, (max-width: 900px) 800px, 1200px"
alt="Description of image" loading="lazy">
</picture>Explanation:
This code snippet combines the <picture> element and the srcset attribute to provide responsive image loading and lazy loading:
- The
<picture>element includes<source>elements for AVIF and WebP formats. - The
srcsetattribute within the<source>elements specifies different image sizes for responsive loading. - The
<img>tag includes a fallback JPEG image and also usessrcsetfor responsive loading. - The
loading="lazy"attribute is applied to the<img>tag to enable lazy loading.
The Big News: Google Now Supports AVIF
Now, let’s shift gears for a moment. There’s been some buzz around a new announcement from Google Search Central: AVIF is officially supported in Google Search. That means Google will index your AVIF images in Google Images and anywhere else images appear in search results.
Why should you care about AVIF? Simply put, it’s the next big thing in image optimization. AVIF (based on the AV1 video compression standard) delivers better quality at smaller file sizes than even WebP, which is already miles ahead of traditional formats like JPEG and PNG.
That said, don’t rush into converting your entire image library to AVIF. Google’s search advocate, John Mueller, who made the announcement, recommends taking your time to evaluate which images should be in AVIF, WebP, or any other format. And if you’re changing file names or extensions, make sure to set up proper server-side redirects to avoid 404 errors.
Wrapping It Up
Image optimization might sound like a small detail, but it can make or break your site’s user experience and search rankings. The right formats, compression settings, and smart loading techniques will speed up your site, make your users happy, and—most importantly—keep Google on your side.
As the web continues to evolve, so do the tools we use to build and optimize it. AVIF is the latest weapon in our arsenal, and with Google’s support, it’s about to become even more mainstream.
The key takeaway? Always be optimizing. A faster, leaner website is not just a nice-to-have; it’s a competitive advantage.
Acknowledgment
This article is inspired by a YouTube video from Google Search Central. You can watch the full episode here.Additionally, you can find Google's announcement on AVIF images for more detailed information.