Canon POWERSHOT SD750 DIGITAL ELPH User Manual page 76

The images you shoot are automatically assigned file numbers. You
can select how the file number is assigned.
i[I
File Number Reset Function
Continuous
Auto reset
A number one higher than the last one recorded is
assigned to the next image. This is convenient for
managing all your images together on a computer
because you avoid file name duplication when changing
folders or memory cards.*
*When a blank memory card is used. If a memory card with
recorded data is used, the 7-digit number for the last recorded
folder and image is compared with the last one on the card, and
the larger of the two is utilized as the basis for new images.
The folder and image number are reset to the starting
value (100-0001).* This is convenient for managing
images on a folder-by-folder basis.
*When a blank memory card is used. If a memory card with
recorded data is used, the number following the 7-digit number
for the last recorded folder and image on the card is utilized as
the basis for new images.
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