Thumbnails not expanding to full size

I am new at this – and developing a website using the Hueman theme hosted by GoDaddy. The site is live and I am preparing to redirect all links from my old site to this one. My site has about 2,500 images so far (all small and regenerated).

Initially all was fine when reviewed live in a browser. However most recently, the thumbnail images that I add to a new page will not expand – and do not show the ‘hand’ when hovered over when viewed in a browser (I use Chrome).

I have looked at the individual image links, copied them into a browser and they come up fine. Here’s and example:
This is one of the first pages I built, all image links work fine:
https://cbc.923.myftpupload.com/kipara-mzuguno/

I built this page over the weekend, no image links work at all:
https://cbc.923.myftpupload.com/ndichu-njuguna/

Because this is an original African paintings website, the thumbnails are critical for the site – so this is really frustrating me. I have nowhere else to turn – your help is appreciated.