Check out the WordPress Plugin of lightGallery

Gallery with custom easing.

You can pass easing property via lightgallery cssEasing setting. Bellow you can find some of the possible values of cssEasing. Demo values are taken from @matthewlein's ceaser

Javascript

$('#custom-easing').lightGallery({
    cssEasing: 'cubic-bezier(0.680, -0.550, 0.265, 1.550)'
})