The thumbnails module will add preview thumbs for each of the slides. You can also set the number of thumbnails responsively.

Here are the options you can set for the thumbnails. To enable the module, simply set the enabled parameter to true.

  thumbnails: {
    enabled: true, // Default: false
    visible: {
      xs: 12,
      sm: 6,
      md: 6,
      lg: 5,
      xl: 5
    position: "bottom", // Positions: top, bottom, left, right
    "class": ""
Option Description
enabled Enable or disable the module.

Values: true, false
visible Specifies how many thumbnails to show in each responsive context.
position Sets the thumbnails position.

Values: "top", "bottom", "left", "right"
class Add a custom thumbnails css class.

Can I make the thumbnails vertical?

Of course! The left and right positions will have vertical thumbnails, while the top and bottom positions will have horizontal thumbnails.