Canon EOS Rebel T1i Instruction Manual page 160

L Erasing Images
3 Erasing All Images in the Card
You can also erase all the images in the card. When the [3 Erase
images] menu is set to [All images on card], all the images in the card
will be erased.
To also erase protected images, format the card instead (p.40).
160
Select [Select and erase images].
2
Select [Select and erase images],
then press <0>.
An image will appear.
Press the <I> button to display
the three-image view. To return to the
single-image display, press the <u>
button.
Select the images to be erased.
3
Select the images to be erased and
press the <V> key.
The <X> icon will be displayed on
the upper left.
To erase other images, repeat step 3.
Erase the images.
4
Press the <L> button.
Select [OK], then press <0>.
The selected images will be erased.