Happy to know your story, About question #1, of course you can create any folder and insert images into the folder, it is your right, if you have right permission settings and there are no problem in your scripts, I guess it is safe and if you do not delete it, they will not be deleted automatically, DH will not remove them of course because you are their customer. If you use wordpress to process images, a good thing is there are many features, for example, thumbnail, this means open your pages more faster, of course there are a few php open source scripts which will “generate” thumbnail in their cache folders so it can works well too, but it need you add these URL manually, by default wordpres will process these steps, also there are many images plugins, which is based on wordpress API, so if you use your folder, maybe this will not work.

Please note, worpdress scripts allow you change your content folder, but it seems this is not match your idea?

About question #2:
There are a few maybe reason, for example, is you meant you create a new site on your sub domain? If so in DH, I remember it will request you enter a new folder to hosting your sub site, so if you use https://images.mydomain.com/picture01.jpg, it is not from the main domain site, right?

Actually, there are a few CDN plugins, which can setting your sub domain to a sub folder, I guess maybe this is what you want? I developed a similar CDN plugin which do this, but my sub domains is not in the same hosting, please search wordpress plugin lists, I believe you can find one which can solve your problem. ??

Not sure do you tried Amazon S3? It is free at the first year and I used a few WP plugins support SYNC images to S3 automatically, hope this have a little help?

Good Luck and have a Good Day. ??

Best Regards,
Tomas

I’d prefer to go with my option #2 and I think I solved my problem. I’m kind of embarrassed about what the problem was, too!! Turns out in my domain settings for the subdomain in Dreamhost, I had the file folder set to the same folder as the main domain. So when I went to a file in https://images.mydomain.com/folderX, it would look for folderX in https://mydomain.com/folderX. When it naturally did not find it, it returned a page not found error. I don’t know how it got set like this, but once I fixed it, it seemed to work.

Also DreamHost has a cloud you can use for images if you’re interested: https://www.dreamhost.com/cloud/cdn/

You can direct link to public images there.

I guess I was more worried that WordPress would delete it. Like I know you’re not supposed to create directories or make edits within the main WP directories and not expect them to get overwritten or messed with in an update. I just wasn’t sure about creating completely different directories there.

When core runs an upgrade, it ONLY would ever delete/edit files it knows about. Deletes are explicit in core (if it’s not on the file that says it’s okay to delete, it won’t touch it). Upgrades replace files, of course, which is why we shout “Don’t edit core!”

But adding your own folder? As long as it’s in the main folder (same level as .htaccess and wp-config) it’s fine ??

(Always make good backups of course!)