question: @ Nullable @ WorkerThread static File writeBitmapToFile ( @ NonNull Bitmap bitmap , @ NonNull File file ) { FileOutputStream fileStream = null ; try { ByteArrayOutputStream byteStream = new ByteArrayOutputStream ( ) ; bitmap . compress ( Bitmap . CompressFormat . PNG , 0 , byteStream ) ; fileStream = new FileOutputStream ( file ) ; fileStream . write ( byteStream . toByteArray ( ) ) ; return file ; } catch ( IOException e ) { Log . e ( TAG , e . getMessage ( ) , e ) ; } finally { if ( fileStream != null ) { try { fileStream . close ( ) ; } catch ( IOException e ) { Log . e ( TAG , e . getMessage ( ) , e ) ; } } } return null ; }
target:  Writes the bitmap to disk and returns the new file.