Trying to find if I can use an external media server to select media and post onto wordpress. I found this plug in https://wordpress.org/plugins/add-external-media/
I suppose you can also upload to popular cloud services and hotlink them to your wordpress site.
I think that loading from external media server is generally not really that supported so still back to the usual practise of just uploading the images into the media library of the wordpress and using the web hosting space until it runs out which is maybe a problem in the distant future which I don’t even know if by then would siteground already upgrade my disk space. Just fixed up my front page. I was getting my image from an external source which caused broken thumbnails sometimes.
You can also insert image from url.
I find that in the end it is important to group and keep the images and video in the same place, you run the possibility of losing them and broken links if you put them all around the place.