No matter how well we think we know our phones, there's always something or other that manages to evade our attention. Don't believe me? If you've got a Samsung phone, chances are you didn't know that your Gallery app contains a hidden menu, chock full of secret options.
To be clear, this isn't new, and Samsung has shipped this since One UI 2.1. If you'd like to try it out, enabling it is rather simple: Head over to settings within the Gallery app and open About Gallery. Now repeatedly tap on the version number until you see a toast that reads [Labs] Gallery labs is enabled. You'll now find the now-not-so-secret menu in the app's settings menu.
There are a bunch of features to be toggled here, but not all of them might be available for your device — the listed One UI versions are the minimum required for each feature to work. For instance, ones listed under One UI 2.5 will only work on phones that run that version or higher. While some of these tweaks have already made their way to the stable experience, there's still a lot to tinker around with. Just keep in mind that you'll have to kill the app from memory and restart it for any changes to be applied.