The Hover Effects settings change the appearance if the thumbnail when someone hovers over it.
With the Hover Effects you can add a color effect to your hover. This means you can have gray thumbs wchich become colorized on hover, or vice versa. If you don’t want either of these effects, set to None.
By selecting Scaling Effect you can make your thumbs scale slightly on hover. In other words, when you over over them they become slightly bigger.
If you would like your captions to be visible when you hover over the thumbnails, select On Hover under Caption Visibility. You can also choose not to have your captions visible on the thumbs, or you can make them visible all the time.
The Transition allows you to change how the hover effects appear. For example, if you’re showing an icon and your caption on hover, you can have them Fade in, slide in, appear instantly and so on.
Finally you can select the icon you want to show on hover. If you don’t want any icon to show, select the first block, which is blank.