Oh you're absolutely right, but when I add icons I usually add the versions I made myself simply because I don't like DISBTN versions of the icons that this site provides, plus I noticed that when I added them last time the size was bigger than the ones I've added, because of that I do it manually.
Another thing with what I've provided in the screenshot with setting the path to "ReplaceableTextures\..." is my way to keep it clean and sorted out when I'll have tons of resources imported, especially when my intention would be to have resources for both SD and HD modes. It's not required, but it's just more clean and easy to understand.
Edit: Oh and thanks for clarification that I don't really need to set the mode to HD if I want to use it properly, I thought it was necessary to have them this way, so I'll keep it in mind in the future.