hi, actually when using the resources folder the asset is encapsulated within the unity file (as part of it) this means that it is not fully dynamically loaded thus if you want to load a file that is not in the resources folder then you need to rebuild your application after adding it to the resources folder, resources folder is always attached and deployed with the unity file but if you want really dynamic loading of assets you need to use the WWW Class either you pick asset bundles for your content streaming (Pro) or you might use its functions to load Textures, Audio, Video and to load models you mights take a look at Mesh Serializer2 at unifycommunity.com.
resources folder will always combine your files and assets within the unity file thus you can't load them unless they are built within the unity file, other content deployed somewhere else can't be loaded through Resources.Load() function.