Having a paid Lightroom subscription syncs photos to cloud storage, but the free version does not and any photos that exist only inside the free app are removed along with the app when the free app is uninstalled.
Thank you for your reply. I have an android phone, so no icloud or itunes. However, it is really weird for Adobe to let their users lose all of their photos and presets when accidentally deleting the app or even losing their phone, given that it is mandatory to log in and create an account in order to use the app. I would expect more than that. There should be at least a pop-up warning when first logging-in to back up our files.