Canon EOS REBEL T8i Advanced User's Manual page 434

Specifying the Range of Images to Be Erased
While looking at the images in the index display, you can specify the first and last images for
a range to erase all the specified images at once.
1.
Select [Select range].
2.
Specify the range of images.
3.
Press the <
Select the first image (start point).
Next, select the last image (end point).
> button.
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