I'm in my master thesis and I have to extract images from about 500 pdf files, some people recommended hexapdf to me for this. I was able to install Ruby and hexapdf and now I'm kinda stuck getting the images out of the pdf's since I don't have a coding background. Any tips?
Thanks in advance.
I tried using the basic command for only one pdf to see what happened by using 'hexapdf images' followed by the pdf name but the result was 'no such file or directory # rb_sysopen'.
If you're getting no such file or directory # rb_sysopen, then that signals that the file you are trying to open does not exist. It sounds like this is probably the PDF that you are trying to extract images from.
I would check that you are following help provided by hexapdf documentation and that the path to your PDF is correct. If the file with your code and the PDF are in the same directory and you are running your code from that file, then you would do something like:
require 'hexapdf'
doc = HexaPDF::Document.open('my_pdf_document_filename.pdf')
If the file is somewhere else on the machine, it may be easiest to use a full file path instead of a relative file path which will depend on your system and such (e.g. /Users/username/thesis/image_processing/files/my_pdf_document_filename.pdf).
I am using Sphinx Documentation tool alongwith LaTeX to generate pdf files.
While trying to include images in the pdf file, I am coming up with the following error during compile:
LaTeX Warning: File `{img_file}.jpg' not found on input line 920.
! Package pdftex.def Error: File `"""{img_file}".jpg' not found: using dra
ft setting.
See the pdftex.def package documentation for explanation.
Type H <return> for immediate help.
...
l.920 ...phinxincludegraphics{{img_file}.jpg}
}
?
These are some key environment variables:
A. In my conf.py, I have defined absolute path as: sys.path.insert(0, os.path.abspath('..'))
B. This is the directory tree:
docs/ # (Sphinx) Documentation folder
_build/
_static/
css/
images/
abc.jpg
img_file.jpg <= This image file is in the root ("_static") directory
_templates/
conf.py
index.rst
modules/ <= Folder containing my source (.rst) files
execute/
file_with_image.rst <= I am trying to put the image in this source file
some_other_file.rst
C. For including the image I am using the following.
.. image:: /_static/img_file.*
D. I have included graphix in conf.py preamble.
Why am I getting this error? What is the source of so many """ quotes in the error message?
Edit
On opening the *.tex file in Tex editor, this is what the code fragment from the image insertion section shows:
\subsection{Add Image}
\label{\detokenize{modules/aud_execution/add_image_with_image_directive:add-image}}\label{\detokenize{modules/aud_execution/add_image_with_image_directive::doc}}
\sphinxstylestrong{Adding an image}
Example of image usage using “image” directive:
\noindent{\hspace*{\fill}\sphinxincludegraphics{{img_file}.jpg}} % ***
Using the Quick Build, the editor throws error as under:
! Package pdftex.def Error: File `"""{img_file}".jpg' not
found: ...
However, when the curly brackets from the image file name, {{img_file}.jpg} are removed and changed it to (line marked ***):
\noindent{\hspace*{\fill}\sphinxincludegraphics{img_file.jpg}} % ***
the document successfully compiles and the image can be seen in the pdf file.
If the .tex file is saved, the pdf file in the _build/latex/ folder shows the image.
So why are the extra brackets being inserted during make latexpdf from the terminal?
Don't place your images under _static. It is special-purpose folder, not for images. E.g. create modules/execute/img/, move image there, and .. image:: img/my-image.png.
Does anyone know how to display a local image in markdown? I don't want to set up a webserver for that.
I try the following in markdown, but it doesn't work:
I suspect the path is not correct. As mentioned by user7412219 ubuntu and windows deal with path differently. Try to put the image in the same folder as your Notebook and use:
On windows the desktop should be at: C:\Users\jzhang\Desktop
The following works with a relative path to an image into a subfolder next to the document:
Solution for Unix-like operating system.
STEP BY STEP :
Create a directory named like Images and put all the images that will be rendered by the Markdown.
For example, put example.png into Images.
To load example.png that was located under the Images directory before.
Note : Images directory must be located under the same directory of your markdown text file which has .md extension.
To add an image in markdown file the .md file and the image should be in the same directory. As in my case my .md file was in doc folder so i also moved the image into the same folder. After that write the following syntax in .md file
like 
This has worked for me.
The best solution is to provide a path relative to the folder where the md document is located.
Probably a browser is in trouble when it tries to resolve the absolute path of a local file. That can be solved by accessing the file trough a webserver, but even in that situation, the image path has to be right.
Having a folder at the same level of the document, containing all the images, is the cleanest and safest solution.
It will load on GitHub, local, local webserver.
images_folder/img.jpg < works
/images_folder/img.jpg < this will work on webserver's only (please read the note!)
Using the absolute path, the image will be accessible only with a url like this: http://hostname.doesntmatter/image_folder/img.jpg
if image has bracket it won't display
.png)
rename the image and remove brackets
Update:
if you have spaces in the file path, you should consider renaming it too or if you use JavaScript you can encode it using
encodeURIComponent(imagePath)
Also, always try to save images and files alike with lowercase, please develop that habit, just my personal view though
Adding a local image worked for me by like so: 
Without the file:// prefix it did not work (Win10, Notepad++ with MarkdownViewer++ addon)
Edit: I found out it also works with html tags, and that is way better:
<img src="file://IMG_20181123_115829.jpg" alt="alt text" width="200"/>
Edit2: In Atom editor it only works without the file:// prefix. What a mess.
Depending on your tool - you can also inject HTML into markdown.
<img src="./img/Isolated.png">
This assumes your folder structure is:
├── img
└── Isolated.jpg
├── README.md
Edited:
Working for me ( for local image )
tree
├── doc
└── jobsSystemSchema.jpg
├── README.md
markdown file README.md is at the same level as doc directory.
In your case ,your markdown file should be at the same level as the directory files.
Working for me (absolute url with raw path)
NOT working for me (url with blob path)
Just add the relative image file route from the markdown file
This worked for me in ubuntu:
Markdown file is in:
/home/gps/Documents/Markdown/
Image file is in:
/home/gps/Pictures/
To my knowledge, for VSCode on Linux, the local image can be normally displayed only when you put the image into the same folder as your .md post file.
i.e. only  or  will work.
Even the absolute path like also doesn't work.
In Jupyter Notebook Markdown, you can use
<img src="RelPathofFolder/File" style="width:800px;height:300px;">
Another possibility for not displayed local image is unintentional indent of the image reference - spaces before .
This makes it 'code block' instead of 'image inclusion'. Just remove the leading spaces.
You may find following the syntax similar to reference links in markdown handy, especially when you have a text with many displays of the same image:
![optional text description of the image][number]
[number]: URL
For example:
![][1]
![This is an optional description][2]
[1]: /home/jerzy/ComputerScience/Parole/Screenshot_2020-10-13_11-53-29.png
[2]: /home/jerzy/ComputerScience/Parole/Screenshot_2020-10-13_11-53-30.png
I've had problems with inserting images in R Markdown. If I do the entire URL: C:/Users/Me/Desktop/Project/images/image.png it tends to work. Otherwise, I have to put the markdown in either the same directory as the image or in an ancestor directory to it. It appears that the declared knitting directory is ignored when referencing images.
Either put the image in the same folder as the markdown file or use a relative path to the image.
just copy the image and then paste it, you will get the output
The basic syntax is . In my case, I used image name as Any\ Image\ of\ your\ choice.png in  instead of  and it was not working. So I would say make sure to check the image directory and also image name doesn't contain spaces if so use underscore(_) instead of space.
Faced issue while using markdown in Jupyter notebook in Ubuntu 18.04.
I got a solution:
a) Example Internet:
b) Example local Image:
TurboByte
I have a C++ project that I'm documenting with Sphinx. To keep the source directory clean, it uses an out-of-source build. I have a tutorial program that gets built as part of the project and generates an image in the build directory, not the project source directory. How can I reference the image in documentation files in the source directory when I have no control over the relative location of the source and build directories of the project?
I've tried using an rst_epilog in conf.py like so:
rst_epilog = """
.. |builddir| replace:: %s
""" % project_build_dir
and then refer to the image like so:
.. figure:: |builddir|/generated.png
but end up with errors like "WARNING: image file not readable: |builddir|/generated.png".
It looks like this is answered in the negative by this question: reStructured Text (Sphinx) : substitution in a file name? . Substitutions cannot be used in image directives to modify the filename and no alternative was offered other than to write a new extension or manually generate an image substitution for every image.
I am writing a documentation and I would like to include links to pdf files or zip archives. How can I achieve that using rst language and sphinx ?
If I do that
here is a pdf file : `pdf <doc/mypdf.pdf>`_
It does not work because, during the compilation sphinx do not copy the contains of the doc directory (I use the makefile generated by sphinx-quickstart).
On the contrary, using the image directive :
.. image:: img/plop.png
sphinx does copy the plop.png image in build directory. How can I obtain the same behavior for pdf or zip archive ?
A solution is to use the :download: “role” (detailed in the sphinx documentation on roles).
Here is a short example assuming you have a file mypdf.pdf in a directory doc. The directory doc and your rst file must be in the same directory:
here is a pdf file :download:`pdf <doc/mypdf.pdf>`
Note that you mustn't put a blank space between :download: and the path to the file.
The image directive also works for PDF files.
.. image:: doc/mypdf.pdf