gphoto2 --set-config /main/camera/shutterspeed=1/20 --set-config /main/camera/resolution=1 --interval 5 --frames 5 --capture-image-and-download --hook-script ./rename_image.sh

./rename_image.sh

#!/bin/bash
# We have to move images from gphoto2 because gphoto2 cannot move them...
PREFIX="IMG_"
[ $ACTION == "download" ] && (mv $ARGUMENT $(exif -t 0x0132 -m $ARGUMENT | sed -e's/:\| //g' -e's/$/.jpg/' -e"s/^/$PREFIX/")) || exit 0