^ This.
IOS tries to make things easy for the user, by pretending not to have a filesystem wherever possible. Which is fine until it isn't.
Android is more sensible, and lets you copy files from one place to another like grown-ups. Possible gotchas are the absence of a file manager app (easily solved by installing one) and it not being entirely clear where the phone is keeping its own photos (you might have to dig around a bit). But ultimately, it's no different to copying files on a Windows/Mac/Linux desktop PC.