Vault is the very good app for privacy and I have been using this app since 1 year and its best in hiding pictures and videos of our private. with the help of vault I can lock my applications from being misuse by others and also can hide images, songs and videos when also if you uninstall vault app the images remains hide and when u again install and keep images unhide then also you can see that images in that gallery like this this vaulis very useful and I recommend to use this app as its the best