There are lots of better diagram editors out there. When I want to create a diagram, I usually just screenshot an OGS demo board or Lizzie (see for instance the diagrams in this thread or this post). The only slight downside there is that I manually have to draw the rectangular region that should be captured, so the image dimensions are not consistent. That was the main reason for me creating the tool for this thread, I wanted to be able to display multiple diagrams in a grid, and that would look very ugly if they had different dimensions.
I don’t know of the top of my head any editor which has a built “export as image” feature, but I’m sure it exists 
If there is some interest, I could make a version of the “Zendo tool” for more general diagram creation, but it would only have the most basic features. I don’t have the skills to create a full-fledged sgf editor like @yebellz’s BesoGo, for instance.