Canon EOS REBEL T7i Instruction Manual page 362

K Protecting Images
3 Protecting All Images in a Folder or on a Card
You can protect all the images in a folder or on a card at once.
If you format the card (p.69), the protected images will also be erased.
Movies can also be protected.

Once an image is protected, it cannot be erased by the camera's erase

function. To erase a protected image, you must first cancel the
protection.
If you erase all the images (p.365), only the protected images will

remain. This is convenient when you want to erase all unnecessary
images at once.
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When you select [All images in folder]
or [All images on card] in [31:
Protect images], all the images in the
folder or on the card will be protected.
To cancel the image protection, select
[Unprotect all images in folder] or
[Unprotect all images on card].