Canon EOS-1D X Mark III Advanced User's Manual page 606

3.
Select [FTP transfer settings].
4.
Select [Automatic transfer].
5.
Select [Enable].
6.
Take the picture.
The captured image is transferred to the FTP server.
Caution
Images cannot be erased during image transfer.
No voice memo can be added when [Automatic transfer] is set to [Enable].
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