A word of caution
These Android apps are designed to hide photos and videos from casual snoopers. Anyone who is really determined and knows what they are doing can probably get at your files, so the best policy is not to let your phone fall into the wrong hands and to set up security on your lock screen.
It’s also worth noting that, just like any other app, an update could cause bugs or it might not play nice with your phone. The only way to be completely sure you never lose any of those photos or videos, is to back them up (that should be a general rule anyway). Before you try any of these apps back up your files, it’s easy to keep them hidden on your computer in a password protected folder.
Hiding folders on Android
It is possible to hide folders from most apps simply by prefixing the name of the folder with a dot. This can prevent folders from being indexed in your Gallery. You can rename directories using any Android file manager. Choose a boring sounding system related name and that will be enough to hide sensitive files from most snoopers.
My top recommendation would be Hide It Pro as it covers most bases and it’s easy to use. If you have any Android privacy apps you’d like to recommend or tips to offer then post a comment and share