There is a parameter you need to pass on the query in order to receive relations and media, it is called ‘populate’
For example: https:localhost:1337/api/posts?populate=*
Note that between v3 and v4 the API path for content types has changed, and now you need to add /api/ between the content type endpoint and the root address.
On the other hand, if you are trying to get images or relations from the “/api/users” or “/api/users/me” endpoint. You are facing a different issue that is related to a bug on the roles & permissions plugin, I just published a solution for that on reddit, see here: https://www.reddit.com/r/Strapi/comments/r7r0ie/comment/i0rub7c/?utm_source=share&utm_medium=web2x&context=3