Manuals are processed automatically and it's kinda technical, but official manuals will make garbage. They're not a single picture like your scanner makes, they're a collection of text and graphics. There's not many of them so I add them manually. Zip is simply a common format most people already know and png/jpg graphics are already compressed so using zip or rar makes little difference.
I don't really understand.
1. Simply uploading the manuals nintendo provides wouldn't work?
2. Why isn't uploading a .rar file an option? Doesn't winrar have better options for higher quality?
I've never done this before, sorry if these are stupid questions