Recover corrupted pictures

Recently I tried to put the pictures in the old Samsung s5 to an sd card. A day later I saw that the pictures and videos were all gone to the lost.dir folder. after some time of searching around the web, I tried to recover them through software and it failed. so now, a new problem has arisen. all the pictures became a folder called UUUUU.UUU. can someone help me recover these corrupted pictures please. thank you.