The Photos app on iOS devices has a special hidden album built-in. While the Hidden Album doesn't secure private photos, it's an easy way to keep images out of the main camera roll. Pictures that are hidden won't show up in Recents or any other album in the photo library. The only place they can be viewed is by opening the Hidden Album.
Apple continues to deliver more granular control over privacy options. The release of iOS 14 adds the ability to decide exactly which photos can be accessed by third-party apps. As always, users can prevent an app from accessing the Photos library or allow an app full access to all images. When specific photos are chosen an app such as Facebook can only read those images, while the rest of your Photos library remains off limits.
Attaching metadata to your photos, like keywords, descriptions and titles, is a great way to make photos easier to find and to add further details that you might want to recall upon later viewing. If you have photos that don't come up in a natural search for their content you can just add a keyword that will ensure it is found when searched for.
Organizing your photos into albums can be a lengthy, painstaking process, especially if you have thousands upon thousands of photos to sort through. Fortunately, the Photos app for Mac has a tool that can be useful for this task - Smart Albums. Basically this tool lets you automatically group your photos by a number of criteria into albums. Unfortunately, and for unknown reasons, smart albums don't synch with iCloud, so you won't be able to create a smart album on your Mac and then view it on your iPhone.
There are a number of artistic reasons to shoot in black and white - it is still seen by some as photography in its purest form as it eliminates the distraction of color, letting the photographer focus on contrast, form, texture and composition. It can also create a mood and give a sense of timelessness to some photos. Whatever your reason, it is easy to take black and white photos with iPhone. You can put a lens filter on before taking the shot so you can see what it will look like, or you can apply it after. Here's how to do it on iPhone: