Related to my earlier question How to reconstruct a blob for an image from a binary string (client side hidden form field) in Google Apps Script, I digged further and realize my critical question is how to create a file in Google Drive if I know exactly the value for each byte of the file?
The DriveApp.createFile function accepts blobs, but I am not sure where to start if I want to create a file with each byte as 0x89,0xFF,0x99,... ?