Canon WFT-E8 Instruction Manual page 110

Changing Settings
Directory Structure of the Target Folder
Configured in [FTP server] 9 [Directory structure].
Selecting [Camera] automatically creates a folder structure matching
that of the camera's (such as A/DCIM/100EOS1D) in the server's root
folder for image storage. If you have created a subfolder in the root
folder by changing the [Target folder] setting, a folder structure such as
"A/DCIM/100EOS1D" is automatically created in that folder for image
storage.
Selecting [Default] will use the root folder for image storage. If you have
created a subfolder in the root folder by changing the [Target folder]
setting, images are saved in that folder.
Overwriting Files of the Same Name
Configured in [FTP server] 9 [Overwrite same file].
When [Overwrite same file] is set to [Disable]
If there is already a file of the same name in the target folder on the FTP
server, the new file is saved with an extension consisting of an
underscore and a number, as in IMG_0003_1.JPG.
When you resend images if initial transfer fails
Even if the transmitter is configured to overwrite files of the same name,
if you resend an image file that could not be transferred initially, the
existing file may not be overwritten in some cases. If this happens, the
new file is saved with an extension consisting of an underscore, a letter,
and a number, as in IMG_0003_a1.JPG.
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