Sphinx to Latex Figure Placement
When modifying conf.py you may have forgot the comma after the 'H'.
Latex figure (float) alignment
'figure_align': 'H',
Works for me on sphinx-doc version 1.4.6.
'figure_align'
Latex figure float alignment, default ‘htbp’ (here, top, bottom, page). Whenever an image doesn’t fit into the current page, it will be ‘floated’ into the next page but may be preceded by any other text. If you don’t like this behavior, use ‘H’ which will disable floating and position figures strictly in the order they appear in the source. Reference Sphinx-doc latex_element.