android 位图存储sd卡,Android将创建的位图保存到SD卡上的目录

我创建了一个位图，现在我想将该位图保存到某个目录中。谁能告诉我这是怎么做的。谢谢

FileInputStream in;

BufferedInputStream buf;

try {

in = new FileInputStream("/mnt/sdcard/dcim/Camera/2010-11-16_18-57-18_989.jpg");

buf = new BufferedInputStream(in);

Bitmap _bitmapPreScale = BitmapFactory.decodeStream(buf);

int oldWidth = _bitmapPreScale.getWidth();

int oldHeight = _bitmapPreScale.getHeight();

int newWidth = 2592;

int newHeight = 1936;

float scaleWidth = ((float) newWidth) / oldWidth;

float scaleHeight = ((float) newHeight) / oldHeight;

Matrix matrix = new Matrix();

// resize the bit map

matrix.postScale(scaleWidth, scaleHeight);

Bitmap _bitmapScaled = Bitmap.createBitmap(_bitmapPreScale, 0, 0,  oldWidth, oldHeight, matrix, true);

(我想将_bitmapScaled保存到SD卡上的文件夹中)