I'm seeing the same thing on domains I've had for many years and built from scratch. The directories and images they are trying to find have never existed on that or any other domain related or linked AFAIK anyway. The queries look like a list they scraped from some robot looking for possible future 'browsing':
- all on one site, along with a ton of .gifs I've never seen or heard of in directories that never existed:
No more 404s, they will be seeing the 403s now.