/** JPEG SOI: FF D8 FF */
export function isJpeg(buffer: Buffer): boolean {
  return (
    buffer.length >= 3 &&
    buffer[0] === 0xff &&
    buffer[1] === 0xd8 &&
    buffer[2] === 0xff
  );
}

export function isPng(buffer: Buffer): boolean {
  return (
    buffer.length >= 8 &&
    buffer[0] === 0x89 &&
    buffer[1] === 0x50 &&
    buffer[2] === 0x4e &&
    buffer[3] === 0x47
  );
}