Canon PowerShot S400 Digital Elph User Manual page 127

Images can beloaded directly from aCF card i fyou have aslot-equipped
notebook computer, aPC card r eader or aCF card r eader.
_I Eject the CF card from the camera and insert it into a CFcard
reader connected to the computer.
If you are using a PC card reader, first insert the CF card into a PC
card adapter (sold separately), and then insert the PC card
adapter into the computer's PC card reader.
El Double-click the icon of the drive containing the CFcard.
Copy the CFcard's images to the desired folder on the hard disk.
The images are contained in the [XXXCANON] folder, which is a
subfolder of the [DCIM] folder on the CFcard. The XXX represents
a number from 100 to 998.