Screenshots of the new Curses mode.
Unfortunately it looks like Curses-mode games are impossible to spectate (well you can watch but graphics will be corrupted like mad). Probably has to do with how ttyrec captures the screen data. Thankfully you can easily change from Curses back to TTY so if people are starting to watch you just flip back to TTY for the time being.
For example, to get things to look like mine set your Putty window to 110x32 (under Window, you HAVE to do this from a new connection not from an existing one). Add the following lines to your Nethack options:
OPTIONS=align_message:bottom,align_status:right,guicolors,windowborders:1,popup_dialog
OPTIONS=term_cols:110,term_rows:32
If you launch in TTY mode with these settings you'll get a bunch of errors about bad options, nothing to worry about. Just hit enter through them and TTY mode will still function normally.