How to convert image into byte array and byte array to base64 String in android?

Try this:

// convert from bitmap to byte arraypublic byte[] getBytesFromBitmap(Bitmap bitmap) {    ByteArrayOutputStream stream = new ByteArrayOutputStream();    bitmap.compress(CompressFormat.JPEG, 70, stream);    return stream.toByteArray();}// get the base 64 stringString imgString = Base64.encodeToString(getBytesFromBitmap(someImg),                        Base64.NO_WRAP);

I wrote the following code to convert an image from sdcard to a Base64 encoded string to send as a JSON object.And it works great:

String filepath = "/sdcard/temp.png";File imagefile = new File(filepath);FileInputStream fis = null;try {    fis = new FileInputStream(imagefile);    } catch (FileNotFoundException e) {    e.printStackTrace();}Bitmap bm = BitmapFactory.decodeStream(fis);ByteArrayOutputStream baos = new ByteArrayOutputStream();  bm.compress(Bitmap.CompressFormat.JPEG, 100 , baos);    byte[] b = baos.toByteArray(); encImage = Base64.encodeToString(b, Base64.DEFAULT);

They have wrapped most stuff need to solve your problem, one of the tests looks like this:

String filename = CSSURLEmbedderTest.class.getResource("folder.png").getPath().replace("%20", " ");String code = "background: url(folder.png);";StringWriter writer = new StringWriter();embedder = new CSSURLEmbedder(new StringReader(code), true);embedder.embedImages(writer, filename.substring(0, filename.lastIndexOf("/")+1));String result = writer.toString();assertEquals("background: url(" + folderDataURI + ");", result);