You might try copying and pasting this in Design > Custom CSS:
/*
** in gallery grid, set a hover over slide effect to
** display slide title on partially transparent
** overlay
*/
.sqs-gallery.sqs-gallery-design-grid .slide
.margin-wrapper .image-slide-title {
position: absolute;
bottom: 0;
width: 100%;
height: 0;
color: white;
background-color: rgba(194, 194, 163, .8);
opacity: 0;
transition: all .25s ease-in;
}
.sqs-gallery.sqs-gallery-design-grid .slide
.margin-wrapper:hover .image-slide-title {
height: 40%;
opacity: .9;
}
This should give you the effect, on hover over a slide, of a partially transparent overlay sliding up over the image and displaying the slide title.
Let me know whether this works and, if so, whether it's the type of effect you have in mind.
-Steve