Salient theme lightbox problems

It would be the best to use another lightbox, that is not included in the theme, such as PhotoSwipe. This theme (otherwise very good) is one of the worst contenders regarding compatibility with custom prettyPhoto solutions.

Please note that it's generally not recommended to use Page Transitions. You could keep the transitions on though, but there is a side-feature that is conflicting in Salient. Do disable it, go to Salient options > Page Transitions > Disable Fade Out On Click and make sure it's ticked.

That's because Salient has a custom implementation of prettyPhoto with CSS rules for it scattered across various CSS files. It would be tedious to remove such rules not to mention you'd lose the ability to update your theme.

Go to Salient options > General Settings > Functionality > Theme Lightbox and choose the Magnific option. This will at least switch the theme's lightbox to Magnific Popup and will load less conflicting CSS for the prettyPhoto you wish to use.

While you are here, make sure that the Auto Lightbox Image Links setting is turned off (unticked) as well.

Set JIG settings > Lightboxes tab > Link attributes section > Link class(es) to:

Also, check out the more general fix for There is no prev/next button in the lightbox.

Unfortunately, you'll need to remove various CSS rules in this file: /wp-content/themes/salient/css/ascend.css and it's a bit scattered. The prettyPhoto-related rules are all prefixed with .pp_ but they are in rules meant for Magnific Popup as well. If you wish, you could comment out the entire block from the first occurrence of a line that contains the prettyPhoto-specific prefix, until the last. The line numbers wouldn't give you an exact pointer here as they are subject to change.

Also, add this to JIG settings > General tab > Custom CSS: