What is the right way to upload images to your website Node js

Am not saying that i dont know how because i tried it before using multer and it works perfectly fine but the thing is these images get saved to a foldet called uploads with a namd and an id that i generatr using js What i want to know : is this the propper way of doing it and if so wherr does that folder go to after hosting your website and does it contain alll the images from my website, i mean it will be a really large folder so where does it go to when hosting ?? PS: And another thing whenever i go to youtube or facebook etc i see a domain like i.ytimg.com containing these images so how is that acheived