Canon EOS-1D X Mark III DSLR Camera (Body Only) - Manual (Page 427)

Index Display (Multiple-Image Display)
1.
Press the < > button.
During image playback, press the < > button.
[ ] will be displayed in the lower right of the screen.
2.
Switch to the index display.
Turn the < > dial counterclockwise.
The 4-image index display will appear. The selected image is
highlighted with an orange frame.
Turning the < > dial further counterclockwise will switch the display
from 9 to 36 to 100 images. Turning the dial clockwise cycles through
100, 36, 9, 4, and single-image display.
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