This should be in sys.txt:

[poi]
picturepoi_show_all_containers=1
picturepoi_has_mypicturepoi=1
picturepoi_scan="/storage/emulated/0/DCIM/"
picturepoi_folder="/storage/emulated/0/DCIM/Camera"

The emulated/0 name of the device is dependent, check it out. If there are images on an external memory card, you must enter it.
The Camera application settings must be set to capture location, if this is not set, it will not show the images in the program.

You can create a folder with a different name where you have the images you want to display in the program. Of course, the path to this folder should be specified.