What does the grayed text mean on the upload page?

I’m looking at images on my upload page, I noticed some of the items have a file name which is greyed out. Does that mean that the files are not referenced by any page?

If I wanted to “clean up” my uploads, would these be safe to delete as they are no referenced anywhere?

That’s right, when it uses gray (and doesn’t link the date) it means that Micro.blog isn’t sure if the upload is used in a specific blog post. However, it might not be safe to delete. If you upload photos separately and then copy/paste the HTML into a new blog post, it will not be linked to the blog post but you don’t want to delete the upload.