Hi Ciaran,
Yet another J4 issue I am afraid.
http://www.joomla4.nepal-systems.co.uk/
If you go to the link above and scroll down to Meet the Trustees you will see that the images are too large and overlap below the footer so are not displayed.
http://www.addinghamcivicsociety.org.uk/
If you go to the link above and scroll down you can see how it looks on the live site.
Both sites use exactly the same images.
However I have noticed on the J4 site that when I add the image, in the slide image identification field it adds extra code at the end. So instead of just being, for example, "images/trustees/Trustees_image_Malcolm_a_200_202.jpg" it is in fact "images/trustees/Trustees_image_Malcolm_a_200_202.jpg#joomlaImage://local-images/trustees/Trustees_image_Malcolm_a_200_202.jpg?width=200&height=200". Also it is not possible to delete this extra code, I can highlight it but the delete or backspace key are not active and will not get rid of it.
Not sure if this is causing the problem or whether it is something else, but if you could please investigate?
Best regards,
Gary