Media library and concrete image instance
Compare standard image block and individual theme markup. If dimensions are missing only in your own template, correct the image output there.
The alt text in the media library does not have to be the only value: a block or builder can store its own text and image size. Therefore, examine the image used in the article and the delivered img edition.
Where to check the setting in WordPress
Select the specific image instance in the article and compare its alt text with the data set in the media library. For own PHP output, wp_get_attachment_image can provide sizes and responsive sources; a hard-coded img tag does not automatically use this output.
Example of this specific finding
Illustrative control case: An image under the introduction does not reserve an area before downloading. As soon as it appears, the following text moves down.
<img src="produkt.webp" width="800" height="600"
style="max-width:100%;height:auto" alt="Roter Rucksack, Vorderansicht">follow-up audit in WordPress
After correcting image URL, check alternative text and selected responsive variant. A global media change does not use as proof that all existing blocks have been updated.
Under throttled connection, the area before and after the image download remains the same. HTML dimensions and responsive CSS must reflect the same aspect ratio.
Derogations and scope
A space already reliably reserved by CSS can also solve the problem. Incorrect width/height values are not an improvement.
Related: WordPress with classic or block theme. SEO plugins and page builders are different; there is no universal menu path for all installations.
Classify the general error
Definition, system-independent causes and further correction examples: Reserve the space for pictures before downloading
Configuration and test signal documentation
WordPress: Image output with sizes and attributes