If you often download videos and music files instead of purchasing them in iTunes, you have to then manually add them to Apple’s native multimedia behemoth. It isn’t difficult, but if you keep downloading media and neglect adding it to iTunes, you get clutter, and lots of it. A much simpler way of doing so is by pasting your media files directly to the Automatically Add to iTunes folder. By adding files directly to this folder, iTunes indexes them and they appear in their respective category when you launch the software. Bear in mind that this means the file is copied to iTunes, and not just indexed at its original location.
Find your iTunes folder on Mac, which will likely be in the Music folder and navigate to iTunes/iTunes Media/Automatically Add to iTunes.
You can go about this in one of two ways; either copy all media files to this folder when you download them, or set your browser or downloader to save files directly to that folder. If you can’t get your browser or downloader to do any of this, you still have the option to create a shortcut to the folder (Make alias on Mac) on your desktop or add it to the Dock.
When you launch iTunes, you will see the added files in their respective category, i.e., audio files under Music and Video files under Movies. Since the entire file is copied to iTunes, your album art will be added as well. You won’t have to wait for iTunes to index, import or update its library, as the file will already be there, no wait required. You can follow suit on Windows and get the same results.