No to knowing why, but will confirm it's been a problem for some time now.
One argument is that some things were lost during a hack several months ago.
Personally watched things disappear early on because of spoopy board volunteers.
/qresearch/ has been an imperfect journey.
If it's a q post it might be here:
https://postimg.cc/gallery/29wdmgyze/
For others, there are some archive arrangements that might have a few images still intact.
Seems to this anon, the more important the image to the puzzle, the more likely it will be missing.