"This “selfie” was created using a specialized pupil imaging lens inside of the NIRCam instrument that was designed to take images of the primary mirror segment

"This “selfie” was created using a specialized pupil imaging lens inside of the NIRCam instrument that was designed to take images of the primary mirror segments instead of images of space. This configuration is not used during scientific operations and is used strictly for engineering and alignment purposes." So they weren't telling the whole truth when they stated that JWST didn't carry any cameras to monitor deployment. Good on them for finding a creative solution.