plies moving from 3 bytes to 3 bytes. When reading a i32 value with 
          // getValue, we are unaligned. As the doc says, results may be
          // unpredictable.
          // To ensure alignment you add -s SAFE_HEAP=1 to your emcc, 
          // the getValue will then crash.
          //
          // let buf32 = new Uint32Array(image.width * image.height * 4);
          // let len = image.width * image.height;
          // for (let ptr = image.data, iDst = 0; iDst < len; ptr += 4, iDst += 1) {
     