It's worth making the point, I think, that if you use a hosting site, and that site changes or you stop using it, your post will loose the link to the photo and may become meaningless. Many good threads from a few years ago have lost all their photos because of that and are considerably less valuable than they were.
Even if you use your own remote site for your photos, and you change the directory structure or file location, the links are lost.
I think the £15 a year for full membership (which supports this site) is well worth it just to be able to upload photos directly into the post that will be preserved for as long as the thread. There is educational value in making threads persistent IMO.
Just my 2p worth