Well, this is not exactly a question, as I\'m not really \"stuck\" on my code, but I\'ve found some strange behavior for Android API regarding accessing the external storage
I finally figured out what was hapenning...
Question 1 : In fact, the file that was created was meant to be used by the system application to retrieve and crop an image from the user's gallery. So my app didn't have to own the WRITE_EXTERNAL_STORAGE permission, as the file was written by the system itself.
Question 2 : I'm not sure. I guess that the Android do not allow to create a temporary file where I was trying to (as it's not the right place for it)