Canon EOS-1D X Instruction Manual page 27

Setting the Size or Type of Images to Transfer
With automatic transfer, you can select which images to transfer when
recording images of different sizes to separate cards, or when recording
both RAW and JPEG images.
Automatic Image Transfer After Each Shot
Select [Communication settings].
1
Select [Network settings].
2
Once [Communication func] is set

to [Enable], you can select [Network
settings].
Select [Set up].
3
Select [Transfer type/size].
4
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