m_galleryIntent = new Intent();
m_galleryIntent.setType("image/*");
m_galleryIntent.setAction(Intent.ACTION_GET_CONTENT);

m_profileButton.setOnClickListener(new OnClickListener()
{
    public void onClick(View v)
    {
        startActivityForResult(Intent.createChooser(m_galleryIntent, "Select Picture"),1);
    }
});

Bitmap yourBitmap;
ByteArrayOutputStream bos = new ByteArrayOutputStream();
yourBitmap.compress(Bitmap.CompressFormat.PNG, 100, bos);
byte[] bArray = bos.toByteArray();

public static byte[] getBytesFromBitmap(Bitmap bitmap) {
    if (bitmap!=null) {
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        bitmap.compress(Bitmap.CompressFormat.JPEG, 70, stream);
        return stream.toByteArray();
    }
    return null;
}