Hello,
Thanks for contacting us and sorry for any inconvenience that might have been caused due to that.
The background images are added as CSS background-image to <div> tags instead of actual images inside the default img tag.
Because of this, Rank Math is unable to detect the presence of images on the page (since they are actually not there, just as background images) and thus is also not able to correctly add them in your sitemap.
For Rank Math to recognize the images, they should be added using the <img> tag. Google and other search engines also do not parse background images. Please refer to the following guidelines by Google: https://developers.google.com/search/docs/advanced/guidelines/google-images#help-us-discover-all-your-images
Hope this helps. Let us know if you need any other assistance.
Hello,
We are super happy that we were able to address your concerns. If you have any other questions in the future, know that we are here to help you.
If you don’t mind me asking, could you please leave us a review (if you haven’t already) on https://wordpress.org/support/plugin/seo-by-rank-math/reviews/#new-post about your overall experience with Rank Math? We appreciate your time and patience.
If you do have another question in the future, please feel free to create a new forum topic, and it will be our pleasure to assist you again.
Thank you.
