I want to ask where is the location of items folder [hero items] for using customized hero images, etc?
This is discussed in more length on the Gamepedia DOTA 2 page for customizing game files. All of these paths are relative to your Dota 2 installation folder, so if your Steam library installs inside the Steam folder and Steam is installed in its default location all of these paths will be prefixed with
C:\Program Files (x86)\Steam\steamapps\common\dota 2\dota or
C:\Program Files (x86)\Steam\steamapps\common\dota 2 beta\dota if you initially installed the game during beta:
- Cosmetic item data:
- Cosmetic item icons:
- Interface customizations:
- Game assets:
- Hero images:
Note these locations may not physically exist on the filesystem as Dota 2 uses VPK files to store all of their data, this means you will need to create the relevant folders if you wish to override the VPK files.