If you mean, do you include the original size image (@1x), when I’ve already included the @2x and @3x version, I’d say, it depends…
Since my images come from hi-res bitmaps or vector images, the first step is scaling it down. Do I do any more work to clean it up other than scaling? Usually, yes if it has any fine lines that would disappear or at least become blurry with anti-aliasing. If so, I will include the original image.
So if most (all?) iOS 12 compatible devices have a Retina display, why bother with the original size if I am just scaling it (and it doesn’t need touching up). Because I don’t know what Apple is going to do with the their standards for interface elements or icons. Maybe in iOS 13 a new multitasking mode will wind up using @1x elements when having multiple apps on-screen.
The assets are usually very small, so it hasn’t been an issue of bloat. If it needs touchups, it’s a must. And otherwise, it’s just to protect my app in future compatibility uses. Not a big thought on my part.