wget -r -np -nH http://your-files.com/files/
It will download all files and subfolders from files directory:
* recursively (-r),
* not going to upper directories, like ccc/… (-np),
* not saving files to hostname folder (-nH).
I am also facing this issue, I tried to do it with the some tips online but It didn't worked. then i get the solution of my slow website loading problem and sort the issue https://globalcool.org/slow-website-loading-problem/