I’m making an app which has a feature that allows users to take screenshots in-app and use them as thumbnails for their creations, which will eventually be uploaded for others to view. Currently, when they press a button the “Shot” command is called and the “File Utils” plugin is used to rename and move the screenshot from the auto-generated “Screenshots” folder to a Thumbnails folder which is created at runtime (if it is not already present). These files are then accessed via the file name to load in the correct thumbnail corresponding to it’s appropriate menu item (i.e. “Thumbnail47.png” is set for option 47).
The only problem is that these folders are accessible and modifiable from the Android files viewer. This means that with this setup, one could theoretically download a random image from the internet (that could be copyrighted, explicit, etc.), rename it to “Thumbnail47.png”, and replace the original to be used in its place then upload.
So, is there a way to validate appropriate thumbnails client-side using unmodifiable properties on the .png files? If not, is it possible to “hide” or prevent these folders from being accessed or otherwise modified by the user? Any information would be greatly appreciated!