Easily export slack channels, dms, or groups, with file attachments and embedded images. View as html or markdown.
Forked from SlackSnap, to go a different direction. If this isn't what you need, check out SlackSnap:
A Chrome extension that exports Slack messages to markdown files. Does what it says on the tin, really. Wrote a blog post about building it.
Note: This is an independent tool, not affiliated with Slack Technologies.