Was able to pinpoint why the pngs weren't uploading. Its because the filename was using scandinavian letters, ÅÄÖ in it. If I remove them it works.
image upload (locally) on Windows
I have NodeBB v 1.1.2 running on Windows 8.1 with default configuration (in particular, I am using the default composer, with Markdown).
When I drag & drop an image in the composer, the image is uploaded locally and a link is generated in markdown:
This does not work, in the sense that no image is displayed in the post.
However, everything works fine if I edit the link and change the first backslash into a forward slash, like this:
I know, stupid Windows...
Thanks for reporting https://github.com/NodeBB/NodeBB/issues/5006
Seems to be related to this bug: https://community.nodebb.org/topic/9418/windows-server-2012-problem-again/31
I'll test if the other bugs are fixed too with this.
Edit: Verified this.