Why Can't I Delete Saved Pictures on My SD Card?by Kevin Smith
Many cameras use SD media cards to save images. If you are having trouble deleting pictures from your SD card, it is likely that your SD card reading device is incompatible with your SD card or that your SD card is locked.
Card Is Locked
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 to be able to delete the pictures.
If you took the pictures on your SD card on one camera, but are using another camera to delete them, you will likely not be able to delete anything. Most cameras only allow you to delete pictures made on that particular model. Return the SD card to the original camera to delete the files.
Outdated Card Reader
If you are having trouble deleting pictures from an SD card through your computer, your SD card reader may be outdated. Refer to the SD card reader manual and take note of the maximum SD speed. If you are attempting to delete pictures from a class 6 SD card with a class 4 SD reader, deletion will not be possible. Find an SD reader that is compatible with your SD card.