Canon EOS M Instruction Manual page 280

p Specifying Images for a Photobook
Specifying All Images in a Folder or on a Card
You can specify all the images in a folder or on a card at one time.
Do not specify for a photobook with this camera images that were already
specified for a different photobook using another camera. The photobook
settings may be overwritten.
You can specify up to 998 images.
RAW images and movies cannot be specified.
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When [x1: Photobook Set-up] is set
to [All images in folder] or [All images
on card], all the images in the folder or
card will be specified.
To cancel the image specification, select
[Clear all in folder] or [Clear all on
card].