the config file can't be loaded

[Suitear]

I use vcsi -c ~/.config/vcsi.conf file.mp4
Processing file.mp4... Sampling... 3/54 Composing contact sheet... Cleaning up temporary files...
but the output file is always in the same directory, not the output folder I set. And the image format cant be changed to png.
There is no timestamp, too.

My config file is as follows:

[vcsi]
IMAGE_QUALITY = 90
METADATA_FONT_SIZE = 20
DELAY_PERCENT = 7
GRID_HORIZONTAL_SPACING = 0
GRID_VERTICAL_SPACING = 0
CONTACT_SHEET_WIDTH = 1280
GRID_SIZE = 3x18
METADATA_POSITION  = hidden
TIMESTAMP_FONT_COLOR = ffffff
TIMESTAMP_BACKGROUND_COLOR  = 000080
verbose = true
IMAGE_FORMAT = "png"
TIMESTAMP_POSITION = sw
OUTPUT_PATH = "/home/thumbnail/"
TIMESTAMP_FORMAT = {TIME}/{DURATION}

but the output directory never be used. and there is no timestamp at all. I don't what's wrong with the config file. Hope there will be an example of config file.