my attempt to fix #3735

an alternative to this would be to do something like
`\DeclareGraphicsExtensions{.pdf}` in the preamble

IPython/nbconvert/templates/latex/sphinx_base.tplx

@@ -1,450 +1,450 b''
 ((= NBConvert Sphinx-Latex Template
 
 Purpose: Allow export of PDF friendly Latex inspired by Sphinx.  Most of the
        template is derived directly from Sphinx source.
 
 Inheritance: null>display_priority 
 
 Note: For best display, use latex syntax highlighting. =))
 
 ((*- extends 'display_priority.tplx' -*))
 
 %==============================================================================
 % Declarations
 %==============================================================================
 
 % In order to make sure that the input/output header follows the code it 
 % preceeds, the needspace package is used to request that a certain
 % amount of lines (specified by this variable) are reserved.  If those
 % lines aren't available on the current page, the documenter will break
 % to the next page and the header along with accomanying lines will be
 % rendered together.  This value specifies the number of lines that
 % the header will be forced to group with without a page break.
 ((*- set min_header_lines = 4 -*))
 
 % This is the number of characters that are permitted per line.  It's
 % important that this limit is set so characters do not run off the
 % edges of latex pages (since latex does not always seem smart enough
 % to prevent this in some cases.)  This is only applied to textual output
 ((* if resources.sphinx.outputstyle == 'simple' *))
     ((*- set wrap_size = 85 -*))
 ((* elif resources.sphinx.outputstyle == 'notebook' *))
     ((*- set wrap_size = 70 -*))
 ((* endif *))
 
 %==============================================================================
 % Header
 %==============================================================================
 ((* block header *))
 
 % Header, overrides base
 
     % Make sure that the sphinx doc style knows who it inherits from.
     \def\sphinxdocclass{(((parentdocumentclass)))}
 
     % Declare the document class
     \documentclass[letterpaper,10pt,english]{((( resources.sphinx.texinputs )))/sphinx(((documentclass)))}
 
     % Imports
     \usepackage[utf8]{inputenc}
     \DeclareUnicodeCharacter{00A0}{\\nobreakspace}
     \usepackage[T1]{fontenc}
     \usepackage{babel}
     \usepackage{times}
     \usepackage{import}
     \usepackage[((( resources.sphinx.chapterstyle )))]{((( resources.sphinx.texinputs )))/fncychap}
     \usepackage{longtable}
     \usepackage{((( resources.sphinx.texinputs )))/sphinx}
     \usepackage{multirow}
 
     \usepackage{amsmath}
     \usepackage{amssymb}
     \usepackage{ucs}
     \usepackage{enumerate}
 
     % Used to make the Input/Output rules follow around the contents.
     \usepackage{needspace}
 
     % Pygments requirements
     \usepackage{fancyvrb}
     \usepackage{color}
     % ansi colors additions
     \definecolor{darkgreen}{rgb}{.12,.54,.11}
     \definecolor{lightgray}{gray}{.95}
     \definecolor{brown}{rgb}{0.54,0.27,0.07}
     \definecolor{purple}{rgb}{0.5,0.0,0.5}
     \definecolor{darkgray}{gray}{0.25}
     \definecolor{lightred}{rgb}{1.0,0.39,0.28}
     \definecolor{lightgreen}{rgb}{0.48,0.99,0.0}
     \definecolor{lightblue}{rgb}{0.53,0.81,0.92}
     \definecolor{lightpurple}{rgb}{0.87,0.63,0.87}
     \definecolor{lightcyan}{rgb}{0.5,1.0,0.83}
 
     % Needed to box output/input
     \usepackage{tikz}
         \usetikzlibrary{calc,arrows,shadows}
     \usepackage[framemethod=tikz]{mdframed}
 
     \usepackage{alltt}
 
     % Used to load and display graphics
     \usepackage{graphicx}
     \graphicspath{ {figs/} }
     \usepackage[Export]{adjustbox} % To resize
 
 
     % For formatting output while also word wrapping.
     \usepackage{listings}
     \lstset{breaklines=true}
     \lstset{basicstyle=\small\ttfamily}
     \def\smaller{\fontsize{9.5pt}{9.5pt}\selectfont}
 
     %Pygments definitions
     ((( resources.sphinx.pygment_definitions )))
 
     %Set pygments styles if needed...
     ((* if resources.sphinx.outputstyle == 'notebook' *))
         \definecolor{nbframe-border}{rgb}{0.867,0.867,0.867}
         \definecolor{nbframe-bg}{rgb}{0.969,0.969,0.969}
         \definecolor{nbframe-in-prompt}{rgb}{0.0,0.0,0.502}
         \definecolor{nbframe-out-prompt}{rgb}{0.545,0.0,0.0}
 
         \newenvironment{ColorVerbatim}
         {\begin{mdframed}[%
             roundcorner=1.0pt, %
             backgroundcolor=nbframe-bg, %
             userdefinedwidth=1\linewidth, %
             leftmargin=0.1\linewidth, %
             innerleftmargin=0pt, %
             innerrightmargin=0pt, %
             linecolor=nbframe-border, %
             linewidth=1pt, %
             usetwoside=false, %
             everyline=true, %
             innerlinewidth=3pt, %
             innerlinecolor=nbframe-bg, %
             middlelinewidth=1pt, %
             middlelinecolor=nbframe-bg, %
             outerlinewidth=0.5pt, %
             outerlinecolor=nbframe-border, %
             needspace=0pt
         ]}
         {\end{mdframed}}
         
         \newenvironment{InvisibleVerbatim}
         {\begin{mdframed}[leftmargin=0.1\linewidth,innerleftmargin=3pt,innerrightmargin=3pt, userdefinedwidth=1\linewidth, linewidth=0pt, linecolor=white, usetwoside=false]}
         {\end{mdframed}}
 
         \renewenvironment{Verbatim}[1][\unskip]
         {\begin{alltt}\smaller}
         {\end{alltt}}
     ((* endif *))
 
     % Help prevent overflowing lines due to urls and other hard-to-break 
     % entities.  This doesn't catch everything...
     \sloppy
 
     % Document level variables
     \title{((( resources.metadata.name | escape_tex )))}
     \date{((( resources.sphinx.date | escape_tex )))}
     \release{((( resources.sphinx.version | escape_tex )))}
     \author{((( resources.sphinx.author | escape_tex )))}
     \renewcommand{\releasename}{((( resources.sphinx.release | escape_tex )))}
 
     % TODO: Add option for the user to specify a logo for his/her export.
     \newcommand{\sphinxlogo}{}
 
     % Make the index page of the document.
     \makeindex
 
     % Import sphinx document type specifics.
     ((* block sphinxheader *))((* endblock sphinxheader *)) 
 ((* endblock header *))
 
 %==============================================================================
 % Body
 %==============================================================================
 ((* block body *))
 ((* block bodyBegin *))
 % Body
 
     % Start of the document
     \begin{document}
 
         ((* if resources.sphinx.header *))
             \maketitle
         ((* endif *))
 
         ((* block toc *))
             \tableofcontents 
         ((* endblock toc *))
 
         ((* endblock bodyBegin *))((( super() )))((* block bodyEnd *))
 
         \renewcommand{\indexname}{Index}
         \printindex
 
     % End of document
     \end{document}
 ((* endblock bodyEnd *))
 ((* endblock body *))
 
 %==============================================================================
 % Footer
 %==============================================================================
 ((* block footer *))
 ((* endblock footer *))
 
 %==============================================================================
 % Headings
 %
 % Purpose: Format pynb headers as sphinx headers.  Depending on the Sphinx
 %          style that is active, this will change.  Thus sphinx styles will
 %          override the values here.
 %==============================================================================
 ((* block headingcell -*))
     \
     ((*- if cell.level == 1 -*))
         ((* block h1 -*))part((* endblock h1 -*))
     ((*- elif cell.level == 2 -*))
         ((* block h2 -*))chapter((* endblock h2 -*))
     ((*- elif cell.level == 3 -*))
         ((* block h3 -*))section((* endblock h3 -*))
     ((*- elif cell.level == 4 -*))
         ((* block h4 -*))subsection((* endblock h4 -*))
     ((*- elif cell.level == 5 -*))
         ((* block h5 -*))subsubsection((* endblock h5 -*))
     ((*- elif cell.level == 6 -*))
         ((* block h6 -*))paragraph((* endblock h6 -*))
 
     ((= It's important to make sure that underscores (which tend to be common
     in IPYNB file titles) do not make their way into latex.  Sometimes this
     causes latex to barf. =))
     ((*- endif -*)){((( cell.source | markdown2latex )))}
 ((*- endblock headingcell *))
 
 %==============================================================================
 % Markdown
 %
 % Purpose: Convert markdown to latex.  Here markdown2latex is explicitly
 %          called since we know we want latex output.
 %==============================================================================
 ((*- block markdowncell scoped-*))
     ((( cell.source | markdown2latex )))
 ((*- endblock markdowncell -*))
 
 %==============================================================================
 % Rawcell
 %
 % Purpose: Raw text cells allow the user to manually inject document code that 
 %          will not get touched by the templating system.
 %==============================================================================
 ((*- block rawcell *))
     ((( cell.source | wrap(wrap_size) )))
 ((* endblock rawcell -*))
 
 %==============================================================================
 % Unknowncell
 %
 % Purpose: This is the catch anything unhandled.  To display this data, we
 %          remove all possible latex conflicts and wrap the characters so they
 %          can't flow off of the page.
 %==============================================================================
 ((* block unknowncell scoped*))
 
     % Unsupported cell type, no formatting
     ((( cell.source | wrap | escape_tex )))
 ((* endblock unknowncell *))
 
 %==============================================================================
 % Input
 %==============================================================================
 ((* block input *))
 
     % Make sure that atleast 4 lines are below the HR
     \needspace{((( min_header_lines )))\baselineskip}
 
     ((* if resources.sphinx.outputstyle == 'simple' *))
 
         % Add a horizantal break, along with break title.
         \vspace{10pt}
         {\scriptsize Input}\\*
         \rule[10pt]{\linewidth}{0.5pt}
         \vspace{-25pt}
 
         % Add contents below.
         ((( cell.input | highlight )))
 
     ((* elif resources.sphinx.outputstyle == 'notebook' *))
         \vspace{6pt}
         ((( write_prompt("In", cell.prompt_number, "nbframe-in-prompt") )))
         \vspace{-2.65\baselineskip}
         \begin{ColorVerbatim}
             \vspace{-0.7\baselineskip}
             ((( cell.input | highlight )))
             ((* if cell.input == None or cell.input == '' *))
                 \vspace{0.3\baselineskip}
             ((* else *))
                 \vspace{-0.2\baselineskip}
             ((* endif *))
         \end{ColorVerbatim}
     ((* endif *))
 ((* endblock input *))
 
 %==============================================================================
 % Output_Group
 %
 % Purpose: Make sure that only one header bar only attaches to the output 
 %          once.  By keeping track of when an input group is started
 %==============================================================================
 ((* block output_group *))
     ((* if cell.outputs.__len__() > 0 *))
 
         % If the first block is an image, minipage the image.  Else
         % request a certain amount of space for the input text.
         ((( iff_figure(cell.outputs[0], "\\begin{minipage}{1.0\\textwidth}", "\\needspace{"  ~ min_header_lines ~ "\\baselineskip}") )))
         
         ((* if resources.sphinx.outputstyle == 'simple' *))
 
             % Add a horizantal break, along with break title.
             \vspace{10pt}
             {\scriptsize Output}\\*
             \rule[10pt]{\linewidth}{0.5pt}
             \vspace{-20pt}
 
             % Add the contents of the first block.
             ((( render_output(cell.outputs[0]) )))
 
             % Close the minipage.
             ((( iff_figure(cell.outputs[0], "\\end{minipage}", "") )))
 
             % Add remainer of the document contents below.
             ((* for output in cell.outputs[1:] *))
                 ((( render_output(output, cell.prompt_number) )))
             ((* endfor *))
         ((* elif resources.sphinx.outputstyle == 'notebook' *))
 
             % Add document contents.
             ((* for output in cell.outputs *))
                 ((( render_output(output, cell.prompt_number) )))
             ((* endfor *))
         ((* endif *))
     ((* endif *))
 ((* endblock *))
 
 %==============================================================================
 % Additional formating
 %==============================================================================
 ((* block data_text *))
     ((( custom_verbatim(output.text) | ansi2latex)))
 ((* endblock *))
 
 ((* block traceback_line *))
     ((( conditionally_center_output(line | indent| rm_ansi) )))
 ((* endblock traceback_line *))
 
 %==============================================================================
 % Supported image formats
 %==============================================================================
 ((*- block data_png -*))
     ((( conditionally_center_output(insert_graphics(output.png_filename)) )))
 ((*- endblock -*))
 
 ((*- block data_jpg -*))
     ((( conditionally_center_output(insert_graphics(output.jpg_filename)) )))
 ((*- endblock -*))
 
 ((*- block data_svg -*))
     ((( conditionally_center_output(insert_graphics(output.svg_filename)) )))
 ((*- endblock -*))
 
 ((*- block data_pdf -*))
-    ((( conditionally_center_output(insert_graphics(output.pdf_filename[:-4])) )))
+    ((( conditionally_center_output(insert_graphics(output.pdf_filename)) )))
 ((*- endblock -*))
 
 ((*- block data_latex *))
     ((* if resources.sphinx.centeroutput *))\begin{center}((* endif -*))((( output.latex | rm_math_space )))((*- if resources.sphinx.centeroutput *))\end{center} ((* endif -*))
 ((*- endblock -*))
 
 %==============================================================================
 % Support Macros
 %==============================================================================
 
 % Name: write_prompt
 % Purpose: Renders an output/input prompt for notebook style pdfs
 ((* macro write_prompt(prompt, number, color) -*))
     \makebox[0.1\linewidth]{\smaller\hfill\tt\color{((( color )))}((( prompt )))\hspace{4pt}{[}((( number ))){]}:\hspace{4pt}}\\*
 ((*- endmacro *))
 
 % Name: render_output
 % Purpose: Renders an output block appropriately.
 ((* macro render_output(output, prompt_number) -*))
     ((*- if output.output_type == 'pyerr' -*))
         ((*- block pyerr scoped *))
             ((( custom_verbatim(super()) )))
         ((* endblock pyerr -*))
     ((*- else -*))
 
         ((* if resources.sphinx.outputstyle == 'notebook' *))
             ((*- if output.output_type == 'pyout' -*))
                 ((( write_prompt("Out", prompt_number, "nbframe-out-prompt") )))
                 \vspace{-2.55\baselineskip}
             ((*- endif -*))
 
             \begin{InvisibleVerbatim}
                 \vspace{-0.5\baselineskip}
         ((*- endif -*))
 
         ((*- block display_data scoped -*))
             ((( super() )))
         ((*- endblock display_data -*))
 
         ((* if resources.sphinx.outputstyle == 'notebook' *))
             \end{InvisibleVerbatim}
         ((*- endif -*))
     ((*- endif -*))
 ((*- endmacro *))
 
 % Name: iff_figure
 % Purpose: If the output block provided is a figure type, the 'true_content'
 %          parameter will be returned.  Else, the 'false_content'. 
 ((* macro iff_figure(output, true_content, false_content) -*))
     ((*- set is_figure = false -*))
     ((*- for type in output | filter_data_type -*))
         ((*- if type in ['pdf', 'svg', 'png', 'jpeg','html']*))
             ((*- set is_figure = true -*))
         ((*- endif -*))
     ((*- endfor -*))
     
     ((* if is_figure -*))
         ((( true_content )))
     ((*- else -*))
         ((( false_content )))
     ((*- endif *))
 ((*- endmacro *))
 
 % Name: custom_verbatim
 % Purpose: This macro creates a verbatim style block that fits the existing
 %          sphinx style more readily than standard verbatim blocks.
 ((* macro custom_verbatim(text) -*))
     \begin{alltt}
     ((*- if resources.sphinx.centeroutput *))\begin{center} ((* endif -*))
 ((( text | wrap(wrap_size) )))
     ((*- if resources.sphinx.centeroutput *))\end{center}((* endif -*))
     \end{alltt}
 ((*- endmacro *))
 
 % Name: conditionally_center_output
 % Purpose: This macro centers the output if the output centering is enabled.
 ((* macro conditionally_center_output(text) -*))
     ((* if resources.sphinx.centeroutput *)){\centering ((* endif *))((( text )))((* if resources.sphinx.centeroutput *))}((* endif *))
 ((*- endmacro *))
 
 % Name: insert_graphics
 % Purpose: This macro will insert an image in the latex document given a path.
 ((* macro insert_graphics(path) -*))
     \begin{center}
     \includegraphics[max size={\textwidth}{\textheight}]{(((path)))}
     \par
     \end{center}
 ((*- endmacro *))