The former armorer -- who was working on the set of "Rust" when the tragedy occurred in 2021 -- was booked into the Santa Fe County Adult Detention Facility Wednesday and did what every inmate has to do when they're processed ... take a photo for the record.

As you can see, Gutierrez-Reed didn't flash any smiles ... and her info is right there on the slate she's holding up. It's interesting, her mug is kinda old-timey, right down to the color grading.

As we reported, Hannah was remanded to custody immediately after the verdict was read aloud in court, where a jury returned a split verdict on two charges she was facing. She was found guilty of involuntary manslaughter, and not guilty of evidence tampering.

Hannah remained stoic throughout the proceeding, but her family was emotional behind her.

The trial lasted about 2 weeks, and prosecutors trotted out multiple witnesses who took the stand and testified against Hannah -- including producers who said, under oath, that she never requested additional armorer time on set (as she'd claimed), and she brushed off a logging system to make sure the weapons were being attended to properly during filming.

Hannah's attorney argued the production itself was already an unsafe environment because of its shoestring budget, and she was overwhelmed with her duties ... but the jury didn't buy it.

Halyna's family released a statement in the aftermath, and they're happy with the result ... while also foreshadowing more justice might be coming when Alec Baldwin's trial begins.