1. Try to delete through My Files: My Files-find the DCIM folder, find the photos/videos that need to be deleted, and click Delete.
2. If you can delete photos/videos, but you can't delete them through the album, it is recommended to try to clear the album data: Settings-Application (Application Manager)-Album-Clear Data (please back up the album contents first).
3. If the photos/videos are stored in an external SD card, please back up the data in the SD card, format the SD card and try again.
4. If it is invalid, please back up the data (contacts, information, photos, etc. ) and restore the phone to the factory settings.
If the problem still exists, please take the purchase invoice, maintenance card and machine to the Samsung service center, and the professional after-sales engineer will help you test it.