Folder -subfolder1 --subsubfolder11 -subfolder2

Hi this is my folder structure. in total i got 40 pictures inside (some are in the subfolders).

I want to replace with a script easily the 40 pictures with new 40 pictures. How to do that? I mean, doing it by hand takes a lot of time, cuz i got hundreds of such folders (working content management). How to automate that with a script?

i have e.g for one instagram account 20 of such folders. How can I “batch” do it?