If you do a clever bit of caching work in your app like we have with our apps Slyp and SlypBusiness, you could even make it insanely cheap.
We have a file manager that is ultimately responsible for images, files, videos and whatnot. It loads the images/files from the downloaded local cache when requested by a feature in the app.
A standard feature uploads and downloads using signed urls obtained from the backend service. The manager increments the file's version in the backend on each successful upload. For download, the manager compares the version against the locally cached version. If there is an update, the new file is downloaded in the background and overwrites the local cache and notifies all features using the file inside the app.