Fancybox - fancyapps.com - Fancy App Store
App Lock and Gallery Vault - Wish you could simply lock all your private apps on your smartphone with just a click?
PhotoSwipe - JavaScript gallery, no dependencies.
AppLock (FOSS) - A privacy App lock FOSS application.
Magnific Popup - The greater part of Lightbox modules will completely preload a picture before showing it.
Hide Secrets - Hide Secrets is an app that allows hiding everything they deem confidential on their smartphone.