Cannot apply line shading

[rsommerard]

Hi,
I have some issue to apply the effect on a jpg or png picture.
When I try to apply the effect, I have this issue.

Traceback (most recent call last):
  File "endurance_line_shading.py", line 339, in effect
    self.draw_path(node, png_temp_file)
  File "endurance_line_shading.py", line 305, in draw_path
    newpath.set('d', simplepath.formatPath(self.drawfunction(image_w, image_h, file)))
  File "endurance_line_shading.py", line 96, in drawfunction
    reader = png.Reader(file)
  File "/home/portable/.config/inkscape/extensions/png.py", line 1376, in __init__
    self.file = open(kw["filename"], "rb")
IOError: [Errno 2] No such file or directory: '/tmp/tmpS4d19b/LineShading.png'

Inkscape cannot find the temp file.
I tried on linux with Inkscape 0.92.3 and macOS with Inkscape 0.92.2.
Moreover, for the preview mode, instead of trying to apply effect on the current picture, the extension open a new Inkscape blank window instead using the current one.