size() {
    var type = this.type()
      , width
      , height
      , buf
      , offset
      , blockSize
      , parser;

    function uint16(b) { return b[1] << 8 | b[0]; }
    function uint32(b) { return b[0] << 24 | b[1] << 16 | b[2] << 8 | b[3]; }

    // Determine dimensions
    switch (type) {
      case 'jpeg':
        buf = Buffer.alloc(this.length);
        fs.readSync(this.fd, buf, 0, this.length, 0);
        offset = 4;
        blockSize = buf[offset] << 8 | buf[offset + 1];

        while (offset < this.length) {
          offset += blockSize;
          if (offset >= this.length || 0xff != buf[offset]) break;
          // SOF0 or SOF2 (progressive)
          if (0xc0 == buf[offset + 1] || 0xc2 == buf[offset + 1]) {
            height = buf[offset + 5] << 8 | buf[offset + 6];
            width = buf[offset + 7] << 8 | buf[offset + 8];
          } else {
            offset += 2;
            blockSize = buf[offset] << 8 | buf[offset + 1];
          }
        }
        break;
      case 'png':
        buf = Buffer.alloc(8);
        // IHDR chunk width / height uint32_t big-endian
        fs.readSync(this.fd, buf, 0, 8, 16);
        width = uint32(buf);
        height = uint32(buf.slice(4, 8));
        break;
      case 'gif':
        buf = Buffer.alloc(4);
        // width / height uint16_t little-endian
        fs.readSync(this.fd, buf, 0, 4, 6);
        width = uint16(buf);
        height = uint16(buf.slice(2, 4));
        break;
      case 'svg':
        offset = Math.min(this.length, 1024);
        buf = Buffer.alloc(offset);
        fs.readSync(this.fd, buf, 0, offset, 0);
        buf = buf.toString('utf8');
        parser = sax.parser(true);
        parser.onopentag = function (node) {
          if ('svg' == node.name && node.attributes.width && node.attributes.height) {
            width = parseInt(node.attributes.width, 10);
            height = parseInt(node.attributes.height, 10);
          }
        };
        parser.write(buf).close();
        break;
    }

    if ('number' != typeof width) throw new Error('failed to find width of "' + this.path + '"');
    if ('number' != typeof height) throw new Error('failed to find height of "' + this.path + '"');

    return [width, height];
  }
Return image dimensions `[width, height]`.

@return {Array}
@api private