[O] Export results of code literal blocks (Jekyll directory structure) xpost emacs.stackexchange

[Jeremy Reeve]

Org-mode newbie here.  Please be gentle.  Posted on Stack Exchange
before I found the official list.

I'm trying to follow the recipe for exporting Org-mode documents for
processing by Jekyll. My publishing org-publish-project-alist is
configured to place exported html in my _posts directory and take
images and place them in _posts/assets with org-publish-attachment.
This modification of directory structure seems to be the root of the
problem.

#+BEGIN_SRC python :results value file
  import numpy as np
  import matplotlib.pyplot as plt

  from mpl_toolkits.mplot3d import Axes3D

  p1 = np.array([0,4,4])
  p2 = np.array([4,-4,4])
  p3 = np.array([2,2,-4])

  fig = plt.figure()
  ax = fig.gca(projection='3d')
  ax.set_aspect("equal")

  #draw the arrow
  ax.quiver(p1[0],p1[1],p1[2],p2[0],p2[1],p2[2],length=1.0)
  ax.quiver(p1[0],p1[1],p1[2],p3[0],p3[1],p3[2],length=1.0)

  ax.set_xlim([-5, 5])
  ax.set_ylim([-5, 5])
  ax.set_zlim([-5, 5])

  plt.savefig('../images/hw1-p3.png')
  return '../images/hw1-p3.png'
#+END_SRC

#+RESULTS:
[[file:../images/hw1-p3.png]]


#+BEGIN_EXPORT html
<figure>
  <img
  src="{{ site.url }}/assets/hw1-p3.png"
  alt="Problem 3 visualisation">
  <figcaption>Problem 3 visualisation</figcaption>
</figure>
#+END_EXPORT html

The end result I would like is to have the link to the result of the
literal code block automatically generated either such that it is not
exported as an inline image (as the relative path is incorrect) and be
forced to manually add a correct link for HTML export or have the
inline image link transformed such that it is correct.

Suggestions like "Don't use Jekyll" are fine so long as it is
accompanied with an alternative and explanation as to why.  I see some
people have written custom Org-mode Jekyll plugins like
https://github.com/eggcaker/jekyll-org and am wondering if these are a
better route.

Also, the above snippet exports everything including the "BEGIN
export" which I think shouldn't happen but I'll examine that
separately.

Regards...Jeremy

Org mode version 9.0.5 (9.0.5-elpa @ /Users/xxx/.emacs.d/elpa/org-20170210/)
GNU Emacs 25.1.1 (x86_64-apple-darwin13.4.0, NS appkit-1265.21 Version
10.9.5 (Build 13F1911)) of 2016-09-18