There is no dearth of lightbox plugins for WordPress, but nearly all of them are either ridiculously bloated, or not responsive, or buggy, or lacking in features, or all of these. WP Featherlight is a new plugin that aims to fix this situation by being extremely light and fast, while supporting native WordPress images, galleries, and even Jetpack galleries. For galleries, WP Featherlight supports navigation by arrow keys or swipe gestures (for touchscreens) to switch between photos. It’s also fully responsive and looks great on small mobile screens.
The one thing you’ve to keep in mind when using WP Featherlight is that your images must link to the media file, not to the attachment page or external content. Link to media file is the default WordPress setting for individual images, and can be easily changed for images in a gallery.
WP Featherlight is available as a free download for WordPress 4.1 and up. We at Tech Orbiter have been using WP Featherlight for the past week, and are very happy with it.