I think maybe it is underestimated how much cognitive load there is in taking a photo. All your attention is going into the act of taking the photo (is it level, is the light right, is it focused, etc.)
That and more importantly that you unconsciously aware that it's saved somewhere that you can recall / review later. So your brain doesn't store the information to long term storage.
In terms of computing, it was only stored on ram, and not going to hdd / ssd, and later will be flushed to be replaced with other info.
Which is not a bad thing if that information isn't crucial for long term.
