I'm a little confused, though. In the screenshot, it says the file name from Q's post was 9Z_ (etc.) and backwards it's "AlertBAHWx71_Z9.png". I thought the file name was already "AlertBAHWx71_Z9.png".
Also, do you know where they got the date of September 26?
Sep 26 is from 9Z
9=Sep
Z=26.
The backward order draws attention to ‘BAHWx71’ which spells backward ‘17xWHAB’ and decoded to Q=17 x=and WHAB=White House Airborne.
The tidbit 9Z in the previous post was a random coincidence. 9Z means Sep 26.