Image SEO has a reputation for being pretty simple. Add some alt text, make sure the file isn’t huge, and move on. In practice, that’s where things start getting more complicated. Alt text tells Google what one picture shows. It says nothing about whether that picture is slowing the page down, sitting too far from the content it’s supposed to support, or hidden from crawlers entirely because of how it was loaded.
This article looks at how leading SEO companies approach image SEO, and why the real work starts well before anyone types a description into an alt field.
Alt Text Still Matters, It Just Isn’t The Whole Job
Alt text is useful, but it doesn’t tell Google everything it needs to know about an image. Google says it looks at the alt attribute along with other information on the page to understand what the image represents. So yes, fill in the alt text, but don’t assume the job is finished once that box is checked. Skip it, or write something lazy like “image1” or “photo,” and there’s an obvious signal a page is throwing away.
But here’s where a lot of sites stop, and it’s a mistake. Writing a good description handles one image on one page. It does nothing for the dozen other factors that decide whether Google ever crawls that image, loads it quickly, or bothers indexing it at all.
Google Pays Attention To What’s Around The Image, Not Just The Image
Search engines don’t look at an image on its own. The text around it helps provide context, including the paragraph, caption, and nearby heading.An image sitting in a gallery by itself doesn’t give Google much context. Put the image next to the copy that explains what people are looking at, and the connection is easier to make. That’s why good SEO teams look at the whole page, not just the alt text. Where the image sits and what surrounds it can matter just as much when you’re trying to give Google some context.
A product photo sitting beside the copy that describes the product gives Google more context to work with. The same photo floating in a hero banner, detached from any copy, doesn’t.
Heavy Images Are A Speed Problem That Gets Mistaken For Something Else
A hero image can look completely fine when you’re sitting at a desktop computer. A large image doesn’t look like a problem when everything loads quickly on a desktop. You usually notice it when the same page is opened on a phone and the image takes its time showing up. Google recommends compressing images and using formats such as WebP and AVIF, but image size can still get caught between development and SEO, with each side assuming the other is dealing with it. And when that image is the largest thing on the page, all that extra weight can slow down LCP.
Lazy Loading Can Work Against The Exact Thing It’s Supposed To Fix
Image SEO often gets boiled down to one thing: writing alt text. That’s part of it, but there’s a lot more going on behind the scenes. An image can have perfectly good alt text and still be too large, load too slowly, or be difficult for Google to find. But that benefit turns into a liability the moment it gets applied to something the user sees the second the page opens.
Google’s performance team, through web.dev, found that lazy loading images already inside the viewport can delay Largest Contentful Paint, one of the three Core Web Vitals metrics Google uses to judge page experience. Google developer advocate Martin Splitt has said on the Search Off the Record podcast that Google’s own site made this exact mistake, because its content management system applied lazy loading to everything by default. If Google can trip over this, it’s not exactly a rare error.
None of this means lazy loading is bad. It just needs to be selective: hold it back from anything visible the instant a page loads, and save it for the images further down the scroll.
Sitemaps And Structured Data Cover The Images Google Might Otherwise Skip
Google has to find an image before it can show it in search, and that’s where some sites run into trouble. A slider or JavaScript might make an image look perfectly normal to someone visiting the page, while the way it was built makes it harder for Google to discover. Using a standard <img> element gives Google a clearer path to the image, and an image sitemap can give it another one, which is especially useful on larger ecommerce, recipe, and publishing sites. Structured data can also help Google understand certain types of content, but whether it’s useful depends on the page and the search features that apply to it.
Structured data can help too, although that depends on the type of page and what Google supports for that content. Product photos, recipes, and some creative works can carry schema markup that tells Google exactly what an image represents, which affects whether it shows up in rich results at all. None of this replaces solid alt text or a fast-loading page. It just closes a gap those two things were never going to close on their own.
Real Results Show Why Image Optimization Matters
There are documented examples of image-related changes producing measurable search results.
Google published a case study involving Kirbie’s Cravings, a food blog run by food blogger and photographer Jennifer. After implementing the max-image-preview:large setting, the site reported a 79% increase in click-through rate from Discover.
There’s a good example of this from Google itself. Brazilian magazine Istoé reported a 30% increase in CTR and a 332% increase in clicks over six months after allowing Google to show larger image previews in Discover. The change had nothing to do with rewriting alt text or compressing the images. It was about giving Google permission to show larger versions of those images in Discover. That matters because image SEO isn’t only about helping Google understand what’s on a page. It can also influence how the page is presented to people and, ultimately, whether they click.
Both case studies were about larger image previews in Discover, not about alt text or image compression. That distinction is important. The lesson is not that one particular image optimization technique will produce a particular percentage increase. The lesson is that how Google is allowed to present a site’s images can affect visibility and click behavior.
There are broader examples of technical SEO producing measurable gains as well. Saramin’s results are a good example of how much can happen when a site tackles its technical SEO problems instead of looking for one quick fix. The company reported a 15% increase in organic traffic after addressing crawling issues in Search Console, and by its 2019 peak hiring season, organic traffic was up 102% from the previous year. It wasn’t an image SEO project, but it shows why SEO often comes down to fixing several things across a site rather than changing one element and calling it done.
What Leading SEO Teams Actually Check
The real work starts after the image gets uploaded. Leading SEO teams aren’t just checking whether the alt text is filled in. They’ll look at the filename, image size, compression, how the image is served on different devices, whether it is being lazy loaded, and whether Google can actually find it. They should also be looking at the page around the image, especially when that image is important to the page or is responsible for the LCP.
It will also look at the actual search data. Google Search Console can show whether pages and images are receiving impressions and clicks, while performance tools can reveal whether oversized or poorly loaded images are contributing to slow experiences. The work is less glamorous than changing a few alt attributes, but that is usually how technical SEO works. The problems that matter most are often buried in the implementation.
What To Ask An SEO Company About Image SEO
Ask what happens after an image gets uploaded. Does the team check its size, decide whether it should be lazy loaded, make sure the right version is being served on mobile, and verify that Google can actually find it? Those answers tell you a lot more than hearing that an agency “optimizes images.”
If you’re looking for help, take a look at our vetted list of SEO agencies and find a team that understands how technical SEO, content, site speed, and image optimization all work together.