
Understanding Changes in Google Discover’s Image Preview Behavior Post-April 26th
In recent weeks, website owners and content creators have observed notable shifts in how Google Discover displays large image previews for articles. Particularly, since April 26th, there appears to have been a significant change affecting websites like primainspirace.cz, leading to a noticeable decline in large image previews and, consequently, a drop in organic traffic from Discover.
Background: Google’s Guidelines for Large Previews
Google’s official recommendations specify that images used for large previews in Discover should be at least 1200 pixels wide. The goal is to ensure high-quality, eye-catching visuals that enhance user Engagement.
The Pre-April 26th Scenario
Prior to this date, many publishers noticed that Google Discover would often showcase large previews for articles even when the main <img>
tag used smaller width
and sizes
attributes—say, 640px. Despite these smaller attributes, the srcset
associated with the image included higher-resolution versions—such as 1600px or 1844px—allowing Discover to display a large, high-quality preview. This behavior implied that Google was selecting images based on the available srcset
and not solely on the rendered size dictated by the HTML attributes.
Post-April 26th Changes
Since April 26th, however, this behavior appears to have shifted:
- Articles with
<img>
tags that specifywidth
andsizes
around 640px—regardless of the presence of largersrcset
versions—are no longer receiving large image previews. - Conversely, articles where the
width
andsizes
attributes are explicitly set to values exceeding 1200px (e.g., 1257px) continue to display large previews normally.
This suggests that Google Discover might now be more strictly adhering to the rendered size of images as dictated by the width
and sizes
attributes, rather than considering the larger versions available in srcset
. In other words, Google may be focusing on the apparent size rendered in the page, rather than just the available image resolutions, to determine eligibility for large previews.
Implications for Content Optimization
For WordPress sites and other platforms employing lazy-loading or responsive images, this change underscores the importance of aligning your image HTML markup with Google’s expectations:
- Ensure that the
width
andsizes
attributes in your<img>
tags accurately reflect the intended display size