This app was mentioned in 4 comments, with an average of 0.75 upvotes
For those who care, here's messaging app with picture sharing abilities but with a focus on security. It's not the same, but it doesn't store your stuff.
https://play.google.com/store/apps/details?id=cm.confide.android
If you install an APK that has the same package name but different signature, then the Play Store won't be able to install/update the app without you first uninstalling the fake app.
If this is the app you are talking about: https://play.google.com/store/apps/details?id=cm.confide.android
Then the package name is cm.confide.android
Check out Confide https://play.google.com/store/apps/details?id=cm.confide.android