On this blog post, the image above the story is an 810x540 JPG image:
<img src="https://cdn.shortpixel.ai/spai/w_810+q_lossless+ret_img+to_webp/https://soxmachine.com/wp-content/uploads/2023/01/USATSI_4652113_168395162_lowres.jpg" data-spai="1" class="attachment-full size-full wp-post-image" alt="Apr 11, 2010; Chicago, IL, USA; Chicago White Sox starting pitcher Mark Buehrle (56) delivers a pitch in the second inning against the Minnesota Twins at US Cellular Field. Mandatory Credit: Mike DiNovo-USA TODAY Sports" decoding="async" itemprop="image" style="aspect-ratio: 3/2;" data-spai-upd="810" width="810" height="540">
However, in text mode, this is instead rendered as a 1200x800 blank (transparent) SVG:
<img alt="Apr 11, 2010; Chicago, IL, USA; Chicago White Sox starting pitcher Mark Buehrle (56) delivers a pitch in the second inning against the Minnesota Twins at US Cellular Field. Mandatory Credit: Mike DiNovo-USA TODAY Sports" class="attachment-full size-full wp-post-image NB-medium-image" src="data:image/svg+xml;base64,PHN2ZyB4bWxucz0iaHR0cDovL3d3dy53My5vcmcvMjAwMC9zdmciIHZpZXdCb3g9IjAgMCAxMjAwIDgwMCIgd2lkdGg9IjEyMDAiIGhlaWdodD0iODAwIiBkYXRhLXU9Imh0dHBzJTNBJTJGJTJGc294bWFjaGluZS5jb20lMkZ3cC1jb250ZW50JTJGdXBsb2FkcyUyRjIwMjMlMkYwMSUyRlVTQVRTSV80NjUyMTEzXzE2ODM5NTE2Ml9sb3dyZXMuanBnIiBkYXRhLXc9IjEyMDAiIGRhdGEtaD0iODAwIiBkYXRhLWJpcD0iIj48L3N2Zz4=" width="1200">
I’ve seen the same on a few other sites, as well. Is there something I can do to help troubleshoot the readability script?