Bitmap logoBitmap = BitmapFactory.decodeResource(mcontext.getResources(), R.drawable.arcnote_logo);
ByteArrayOutputStream logoStream = new ByteArrayOutputStream();
boolean res = logoBitmap.compress(Bitmap.CompressFormat.PNG,100,logoStream);
//将图像读取到logoStream中
byte[] logoBuf = logoStream.toByteArray();
//将图像保存到byte[]中
Bitmap temp = BitmapFactory.decodeByteArray(logoBuf,0,logoBuf.length);
//将图像从byte[]中读取生成Bitmap 对象 temp
saveMyBitmap("tttt",temp);
//将图像保存到SD卡中
public void saveMyBitmap(String bitName,Bitmap mBitmap){
 File f = new File("/sdcard/" + bitName + ".png");
 try {
  f.createNewFile();
 } catch (IOException e) {
  // TODO Auto-generated catch block
 }
 FileOutputStream fOut = null;
 try {
  fOut = new FileOutputStream(f);
 } catch (Exception e) {
  e.printStackTrace();
 }
 mBitmap.compress(Bitmap.CompressFormat.PNG, 100, fOut);
 try {
  fOut.flush();
 } catch (IOException e) {
  e.printStackTrace();
 }
 try {
  fOut.close();
 } catch (IOException e) {
  e.printStackTrace();
 }
}