Once you’ve downloaded a bunch of photos or videos to the Files app on your iPhone or iPad, you might be wondering if you can copy them to your Photos library for quick access when you need them. The answer is yes, and it’s not complicated to do.
First, open the Files app on your device and navigate to the folder containing the media files (images, videos) you want to move to your Photos library. In this example, we’ll be working with media files in the Downloads folder, but you can of course work with any other folder in Files, such as your Dropbox or iCloud Drive.

Once you've located the media files you want to copy, you'll have a few different options for working with the files.
If it's an image or video, tap it to open the detail view.
If you want to select multiple files on your iPhone, tap the ellipsis button (three dots in a circle) in the upper-right corner of the screen and select “Select.” (On an iPad, just tap “Select.”) Then check the items you want to copy to your Photos library.

Once you have selected your file, tap the “Share” button, which looks like a rectangle with an arrow pointing up. On iPad, it is in the upper-right corner of the screen. On iPhone, it is in the lower-left corner.

In the share menu that pops up, tap “Save Image” or “Save Video.” If you selected multiple photos or videos, tap “Save X Items,” where X is the number of items you selected.

That’s all there is to it. The next time you open the Photos app, you’ll see the photos or videos you copied from the Files app appear in your “Recents” album.
You can also use this method to copy media files from the Files app to iCloud Drive or Dropbox.