A strange problem has appeared in the tagged items view of articles on my website https://eume.upf.org. See for example https://eume.upf.org/where-we-are/western-europe/germany, where the intro images of the more recently created articles appear to be smaller than the others, even though they are all 200x200 px.
I observed that these top 4 articles have the additional "HTML source code" marked in bold here: <img src="/images/germany/Germany-2023-02-07-Stuttgart.jpg" alt="UPF-Stuttgart Observes Interfaith Harmony Week" width="200" height="200" loading="lazy">
When I observe these articles in the normal category blog, the intro image is the same size as the others, so this problem seems to only affect the tagged items view of articles and only the newly entered articles.
It transpires that when I put these images in the intro image field of the "images and links" tab, "?width=NNN&height=NNN", where NNN is the actual size of the image, is being added at the end of the image path and filename. I thought perhaps this was coming from the editor, but I changed from JCE to TinyMCE and got the same result. I've also tried disabling a certain number of plugins but nothing changed. I also tried restoring a backup of the website on XAMPP when it was still Joomla 4.2.8, but this did not have any effect.
I discovered that the "HTML source code" in the display of the image is coming from layouts/joomla/html/image.php, as explained in: About Joomla 4 Lazy Loading feature.
However, I am not getting this on my other Joomla 4.2.9 websites, so I'm still not sure what's triggering this. Some posts refer to a lazy loading plugin, but this does not seem to be installed any more.
Does anyone have any ideas about this?