Be aware that images can be deleted from your SD card when installed KiOS! They are removed (first in, first out) when the partition is almost full.
How does it work?
The init script of the machinery contains some logic which checks continuously if the SD card has enough space. When the SD card is more than 90% full, it will start erasing images from the image directory; note that this mechanism is only available when installed KiOS.
How to disable deletion?
You can disable the deletion by removing the lines from the init script at /etc/init.d/S85machinery. You'll notice that when you try this you'll get an Read only error. This is because we don't want to have the filesystem to be writable; data corruption. Note that you will need to enable write mode first, before you can edit this file; read more here.
After you've disabled read only, you can remove the lines from the init file, enable read only again, and reboot the system. From this point no images will be removed from your SD card.
What happens when disk is full and I disabled deletion?
When you disabled deletion, and your SD card gets 100% full, the system will be malfunctioning; e.g. Kerberos.io will still run, but images will not be stored.