The software will install/download everything in the original installation directory. If you install the application from scratch and log in, it will download all your packs again so you can use them.
So I’m not sure what files you referring to here, to be honest. If you Save/Export any PNG or LBD files, they are where you saved them and are not tied into the software at all. If you created new items or clothing by using the developer package, then you needed to copy the custom pack to the installation directory for it to work, so it’s up to you if backed those up, or if you have the source files.