However, neither of these notification features prevent someone from taking the screenshot in the first place, and they could easily take advantage of the app’s biggest loophole: taking a photo of the screen with another device.
Messaging apps that employ end-to-end encryption, like Signal and Whats App, are great for protecting your various states of undress from hackers and government surveillance.
Snapchat will display a particular icon (an arrow with spikes) when a screenshot of your Snap has been taken.
You’ll have to delete the chats manually from your cloud service account. Go to File New Image From Folder and select the folder you want to protect. Under Image Format options, select read/write so you can still add and delete photos at your leisure.
If you must, the best way to save your most sensitive photos is through the aforementioned method: on an encrypted hard drive in a password-protected folder. Under Encryption options, select 128-bit AES encryption and add a password. You can do it for individual files too, through the Preview app.
I’d recommend using an app with audited, full encryption (like Signal or Whats App) and deleting the photos and videos right after they’re sent, but these apps are also good options for adding another layer of security.
Privates (free, i OS) is a good app for preventing screenshotting.
You can choose to protect the photo with one security measure, or all of them at once.