function replaceJPEGHead(blob, oldHead, newHead) {
    if (!blob || !oldHead || !newHead) return null
    return new Blob([newHead, blobSlice.call(blob, oldHead.byteLength)], {
      type: 'image/jpeg'
    })
  }
Replaces the head of a JPEG Blob

@param {Blob} blob Blob object
@param {ArrayBuffer} oldHead Old JPEG head
@param {ArrayBuffer} newHead New JPEG head
@returns {Blob} Combined Blob