1.打开根目录下test.jpg

Bitmap bm = BitmapFactory.decodeFile(Environment.getExternalStorageDirectory().getAbsolutePath()+"/test.jpg");

int[] pixels = new int[bm.getWidth()*bm.getHeight()];

bm.getPixels =(pixels,0,bm.getWidth(),0,0,bm.getWidth(),bm.getHeight() );

Bitmap bm1 = bm.copy(bm.getConfig(),true);//bm is not Mutable ,像素值不能改

bm1.setPixels(pixels,0,bm.getWidth(),0,0,bm.getWidth(),bm.getHeight() );

saveBitmap("test2",bm1);

ImageVie imgview = (ImageView)findViewById(R.id.imageView1);

imgview.setImageBitmap(bm1);

2.保存图片

public void saveBitmap(String name,Bitmap mBitmap){

File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath()+"/"+name+".png");

file.createNewFile();

FileOutPutStream fout = null;

fout = new FileOutPutStream(file);

mBitmap.compress(Bitmap.CompressFormat.PNG,100,fout);

fout.flush();

fout.close();

}

原文：http://www.cnblogs.com/mlj318/p/4512355.html