.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;
}
Currently getting some hiccups with Firefox. This is on SquareSpaces side of things. I already spent about 3 hours trying to get this to work, and I don't feel like digging though a million lines of code again. (The standard transition doesn't work right in Firefox either, its just too fast to notice).
Anyway, this works with every other browser that I tested. I added 1000ms to the default values, I am not sure if the 200ms differences matter much, but I left them. You can probably leave out the importants, and honestly, you don't need the webkits, but I guess if someone is on a very old browser its good to toss them in there.
I will attempt to get this over to SS to see if they can fix the Firefox issue. It fades sometimes, snaps the next, not sure whats up.