Preferred Images Storage
When plugin needs to have a valid URI for an image, it can be saved using the Internal or External storage. In case saving attempt is failed, an alternative option will be used. You can define if Internal or External storage should be a preferred option.
By default, files saved to the internal storage are private to your app, and other apps cannot access them (nor can the user, unless they have root access). This makes internal storage a good place for internal app data that the user doesn't need to directly access. The system provides a private directory on the file system for each app where you can organize any files your app needs.
When the user uninstalls your app, the files saved on the internal storage are removed. Because of this behavior, you should not use internal storage to save anything the user expects to persist independenly of your app. For example, if your app allows users to capture photos, the user would expect that they can access those photos even after they uninstall your app. So you should instead save those types of files to the public external storage.
To learn more, read how to save a file on internal storage.
Internal cache files
If you'd like to keep some data temporarily, rather than store it persistently, you should use the special cache directory to save the data. Each app has a private cache directory specifically for these kinds of files. When the device is low on internal storage space, Android may delete these cache files to recover space. However, you should not rely on the system to clean up these files for you. You should always maintain the cache files yourself and stay within a reasonable limit of space consumed, such as 1MB. When the user uninstalls your app, these files are removed.
For more information, see how to write a cache file.
When force internal storage is chosen plugin will only be saving images to the internal storage, which means 2 things.
- You will able to remove
- Devices that do not have internal storage or have not enough space will not able to save an image internally.
Every Android device supports a shared "external storage" space that you can use to save files. This space is called external because it's not guaranteed to be accessible—it is a storage space that users can mount to a computer as an external storage device, and it might even be physically removable (such as an SD card). Files saved to the external storage are world-readable and can be modified by the user when they enable USB mass storage to transfer files on a computer.
So before you attempt to access a file in external storage in your app, you should check for the availability of the external storage directories as well as the files you are trying to access.
Most often, you should use external storage for user data that should be accessible to other apps and saved even if the user uninstalls your app, such as captured photos or downloaded files. The system provides standard public directories for these kinds of files, so the user has one location for all their photos, ringtones, music, and such.
You can also save files to the external storage in an app-specific directory that the system deletes when the user uninstalls your app. This might be a useful alternative to internal storage if you need more space, but the files here aren't guaranteed to be accessible because the user might remove the storage SD card. And the files are still world readable; they're just saved to a location that's not shared with other apps.
For more information, read how to save a file on external storage.