First time use of Piwigo, but fairly competent around websites/databases etc

Piwigo 11.5
Bootsrap Darkroom
Fotorama
gThumb

Just a test album https://rosalindyoung.com/piwigo/piwigo … category/3

Click on an image and it opens up but with a white background and parts of the menu top and bottom but click on the start slideshow and it opens correctly.
I have uninstalled/reinstalled reverted to original settings and it is still the same. Deactivating gThumb doesn't make any difference either.

Stumped.
Rosalind