Mr Mag,
When you File>Place (the usual way of getting an image into a document, maybe with Link ticked so it does not bloat the file size) or whatever, the image shows at a resolution of 72PPI.
You may scale it down so it looks as little as you wish.
That will not influence the actual image size in pixels x pixels, and all the information/detail/quality will still be there.
Illy is really focused on vector artwork, so she cares (and knows) little about raster images, chiefly seeing them as bunches of pixels or whatever kept in (Bounding) Boxes.