I noticed in private messages, the design is changed and now we can do this without leaving the page: (which is accessing the full toolbar for post editing/submission)
but on posts and topics, we can't do that. the quick reply only offers this:
please apply the same design to quick reply in posts. sometimes I only need to add an image to a post and for that I have to reload the whole page again.
it also saves time to have access to the full toolbar in quick reply.