Images not displaying in printed version

Both sites are different, the code in the content is also different

<img width="450" height="338" src="https://www.spanish-property-sales.ru/wp-content/uploads/2015/06/47666b1403245eac7_large.jpg" class="single-listing-image wp-post-image" alt="47666b1403245eac7_large.jpg">

Whereas the second one is
<img width="800" height="533" src="https://www.morairaconstruction.eu/wp-content/uploads/2016/01/1E0A9532__A.jpg" class="single-listing-image wp-post-image" alt="1E0A9532__A" srcset="https://www.morairaconstruction.eu/wp-content/uploads/2016/01/1E0A9532__A-300x200.jpg 300w, https://www.morairaconstruction.eu/wp-content/uploads/2016/01/1E0A9532__A-768x512.jpg 768w, https://www.morairaconstruction.eu/wp-content/uploads/2016/01/1E0A9532__A-250x167.jpg 250w, https://www.morairaconstruction.eu/wp-content/uploads/2016/01/1E0A9532__A.jpg 800w" sizes="(max-width: 800px) 100vw, 800px">

So I am not sure how the images are inserted the post? Is it within the post content?

Hi Lester,

Thanks for coming back to me.
The posts are created using a single-post-template. this is the same for both websites apart from the addition of an additional tab for floor-plans in the non functioning site. If I use the same single listing template from the functionig website I have the same issue with the missing images.
I will look at why the image code is different and come back to you.

Stuart