How to transfer from photos in files to photo library?

Hello,

If drag-and-drop does not work then you try this:

Open the folder in Files that contains the photos you wish to save to the Photos application > Tap Select > Select All > Share > Save Images.

Hello,

You could use drag-and-drop.

How to drag and drop on iPad — Apple Support

I’m not sure what you mean by file folders. If you mean photos that are in the files app, you can copy them and paste them into an email and email them to yourself and save them to the photos app.

It’s not a real elegant solution, but it works. Depending on what you are doing with them, the resolution may not be great.

I have similar issue but your remedy is not working. I transferred few folders of photos through USB which got stored in Files. Now I want to transfer it to Photos but not able to do so.