Hey @MaggieBovary
Lets try this...... I commented out one part of the last line. That line can be removed is this works.
Edit: Also, if this doesn't work, try turning off the dots for the different images, I am not sure if that will matter, but if it does I will look into it. There's like 300 lines of code for the slide show, so its a disaster to mess with.
.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;
}