Try using a file manager app (you should have My Files). But don't Move them, Copy them to where you want them. (Long-press on one of them and they'll all get check boxes, with the one you long-pressed checked. Check the boxes on the other ones you want, then tap Copy [in the menu]. Go to where you want to move them and tap Paste [I think it says "paste here"]. Check them all to make sure they copied correctly, then go back to where they came from, check them all again and delete them from there.)
If a Move blows up in the middle, you can lose both the source and the destination files. If a copy blows up in the middle, you still have the originals.