How does Google choose which images to display in the SERPs?

What does Google mean by "algorithmic extraction" of images?

Google does not simply take the main image from a page at random. The algorithm analyzes the full content of the page to identify which image is most relevant to the user's query.

This selection is based on several signals: the alt text of the image, the immediate textual context (title, caption, surrounding paragraphs), the HTML structure (tag og:image, schema ImageObject), and the position of the image in the DOM. Google favors images that have a strong semantic link with the main content of the page.

Why display images even for non-imageable queries?

Traditionally, it was thought that images in the SERPs mainly pertained to transactional or inspirational queries (fashion, decor, recipes). However, Google has extended this principle to almost all types of results.

The stated goal is to enhance the user experience by allowing a faster visual scan of the results. A relevant image can trigger a click where a simple title/meta might go unnoticed. This is particularly true on mobile, where vertical space is limited and the eye is more easily attracted to an image.

Which pages are concerned by this image display?

All indexable pages can potentially have one of their images displayed in regular SERPs. This goes beyond rich results like recipes or products.

This phenomenon is observed on blog articles, e-commerce category pages, technical sheets, and even institutional corporate pages. The logic is simple: as soon as a page contains one or more usable images, Google can decide to display it if the algorithm believes it enhances user understanding of the result.

• Algorithmic extraction: Google chooses the most relevant image based on semantic context and HTML structure
• UX and CTR impact: a well-chosen image can significantly increase the click-through rate from the SERPs
• Universality: all pages with images are potentially affected, not just those inherently visual
• Technical signals: alt tags, schema ImageObject, og:image, and textual context are the main levers
• Mobile-first: image display plays an even more crucial role on mobile where space is constrained

Is this statement consistent with on-the-ground observations?

Yes, but with significant gray areas. On paper, the display of images in the SERPs follows a logical algorithmic approach. However, in practice, inconsistencies are observed: irrelevant images being displayed, well-optimized pages never benefiting, and variations between desktop/mobile that are hard to explain.

Google remains vague about the exact selection criteria. Talking about "relevant algorithmic extraction" without detailing the weights is a bit like saying "we're doing good SEO." [To be verified]: The actual impact of the image's position in the DOM relative to the weight of the textual context remains unclear. A/B tests on this point yield contradictory results across niches.

What nuances should be added to this claim?

Google never guarantees the display of an image, even if perfectly optimized. The algorithm may decide not to display anything if no image seems sufficiently relevant or qualitative. It's also observed that certain sectors (finance, legal, health YMYL) see far fewer images in the SERPs, likely due to editorial caution.

Another point: Google talks about "improving user experience," but it's also a lever to capture attention and reduce bounce rates to other engines or sources. User experience is rarely altruistic. Finally, this statement completely overlooks the issue of copyright and conflicts with image publishers—a hot topic in Europe and the United States.

In what cases does this logic not apply?

Some queries never trigger images in the SERPs, regardless of optimizations: purely informational technical queries, navigational queries to well-known brands, local queries with a dominant local pack. The format of the SERP itself dictates whether an image can be displayed.

Moreover, if a page competes with rich snippets (FAQ, How-to, etc.), the available space for an image drastically reduces. Google will often favor the rich snippet over the image. Finally, in ultra-competitive queries with many ads, the organic image may be pushed out of the initial viewport, negating its CTR benefit.

What should be optimized concretely to maximize image display?

First priority: descriptive and keyword-rich alt text without keyword stuffing. Google heavily relies on this tag to understand the content of the image. A vague alt text like "image1.jpg" or "photo" will never be retained.

Next, the immediate textual context matters greatly. Positioning the image closest to the most relevant H2 or H3, adding an explicit caption (figcaption tag if possible), and ensuring that the surrounding paragraph reflects the semantic field of the target query. Google cross-references these signals to evaluate relevance.

What formats and technical specifications should be favored?

The WebP or AVIF formats are now recommended for their quality/weight ratio. Google indexes these modern formats without issue and may even prefer them for their performance. As a fallback, an optimized JPEG (compression 80-85%) remains acceptable.

Regarding dimensions, aim for a 16:9 or 4:3 aspect ratio with a minimum width of 1200px for main images. Google may automatically crop, but an image too small or with an exotic ratio risks being ignored. The weight should ideally remain below 200 KB—a compromise between visual quality and loading time.

How to structure data to signal key images?

Using schema ImageObject in the JSON-LD of the page explicitly indicates which image is most representative. This doesn't guarantee anything, but it's a strong signal for the algorithm. Include contentUrl, caption, and, if applicable, creator with credits.

The tag og:image is also taken into account, especially for social sharing, but Google can use it as a prioritization signal. Avoid multiplying og:image—one, the most relevant, is sufficient. Lastly, remember to provide EXIF data if the photo is original: this can affect the freshness and perceived originality of the content.

• Write descriptive alt texts integrating the semantic field of the target query
• Place strategic images as close as possible to relevant H2/H3 titles
• Favor WebP or AVIF, aspect ratio 16:9/4:3, width ≥ 1200px, weight < 200 KB
• Implement schema ImageObject in JSON-LD for main images
• Specify og:image (one only) and figcaption when the CMS allows it
• Test SERP display via preview tools (e.g. Google Search Console, browser extensions)