Just building a theme but I am stuck with attachment images.
When I add images from the library to posts (or pages) and link them to the "attachment page" I get a 404 error. The link is like "http://localhost:8888/mywebsite/name-of-image".
When I add images directly to posts (upload in post, not taking one I added to library before) it works. The link is like "http://localhost:8888/mywebsite/name-of-post/name-of-image".
I tested with "twentysixteen" theme - same problem. What am I doing wrong here?
Permalinks are okay I think (refreshed it some time).