The number one reason – you’ve inadvertently locked your SD, Mini or Micro SD Memory Card. On the side of all memory cards, there is a small slider. Check to see if your SD card is locked. If the slider on the left side of the card is in the "locked" position, you will not be able to delete photos. Move the slider away from the "locked" position.
SD-Stands for Secure Digital...but is becoming the most common memory card used today
Now when you reinsert the Memory card into your Smartphone, camera or camcorder - you will be able to take photos. When you put the Memory card into your computer you will be able to copy all photos, music, and other data to and from the computer. You will also now be able to delete anything not wanted.
Remember, never delete or remove the DCIM folder that is on every memory card.
What is the DCIM Folder? DCIM (Digital Camera IMages) is the default directory structure for digital cameras and is there to keep your photos and or videos organized. When you put a memory card into a camera, camcorder or Smartphone, the camera device immediately looks for a ‘DCIM' folder. If it doesn't find such a folder, most cameras will create one.