Welcome to Android Central! You can't stop apps from doing that. But you can try to prevent those images from showing up in your gallery apps. The problem is that those app designers aren't properly including a ".nomedia" file in the directory where the app is saving those images. Without a .nomedia file in a directory, the phone's media scanner will add any images in that directory to the gallery database.
Use a file manager app to locate the directories that contain these images, and then add a blank file titled .nomedia. Now see if they go away in the galleries.
11-07-2017 11:25 PM