I just typed up a post, including an image upload, and then when I tried to submit the post I found that the community was read only and I couldn’t post. I did a copy and paste of all the text, including the image link, and posted it somewhere else.
I’m assuming there is some background task to prune orphaned images and am now wondering if the image I uploaded is in danger of disappearing because it is no longer referenced by the post it was uploaded in/for?

I don’t think images are tied to posts that way. Once media is uploaded is has an independent URL separate from the post.
You can see the image on the uploads tab of your profile page if you are using the default lemmy-ui.
This is correct. At this time, we don’t do any pruning or cleanup of images.
It might be necessary way down the road, but lots of free storage space for now
I never noticed that - thank you