I had try your extension with appinventor.
But the quality of the image is very very poor.
In fact I had made a program to take picture each 5s and enable flash befaore and close after.
But focus is very bad, quality is very bad, lot of snow pixel on the image.
So do you have solution to have very good picture as I use normaly my camera in the same condition.
In fact I take picture in dark condition dans enable the flash just befaire taking the picture and disable the flash just after.
Thanks to help.