MartyNZ

This worked for me. Although, not straight away. I pasted the code in, then had to add another gallery image block, refresh the browser then worked. .gallery-fullscreen-slideshow-item-img{ transition: opacity 1600ms ease-in-out !important; -webkit-transition: opacity 1600ms ease-in-out !important; -ms-transition: opacity 1600ms ease-in-out !important; -moz-transition: opacity 1600ms ease-in-out !important; -o-transition: opacity 1600ms ease-in-out !important; } //.gallery-fullscreen-slideshow[data-transition="fade"] .gallery-fullscreen-slideshow-item[data-active="true"] .gallery-fullscreen-slideshow-item-src{ transition: opacity 1400ms ease-in-out !important; -webkit-transition: opacity 1400ms ease-in-out !important; -ms-transition: opacity 1400ms ease-in-out !important; -moz-transition: opacity 1400ms ease-in-out !important; -o-transition: opacity 1400ms ease-in-out !important; }