@milindmore22 You are just great… You were absolutely spot on. The real problem was with the styling code – <style>img:is([sizes="auto" i], [sizes^="auto," i]) { contain-intrinsic-size: 3000px 1500px }</style>
I googled it and found that this code was inserted in WP 6.7.1 and included in wp-includes/media.php. I commented this code in media.php, cleared the cache, and tested the amp site. The error is gone. I don’t know whether it’s the right way or not, but commenting on this code resolved the issue.
I was struggling to sort out the breaking of my AMP site, but you identified it correctly. Thanks a lot once again for your prompt reply and for helping me resolve this issue. Thanks…