org-babel latex picture resolution very low

Question

I try below code in ubuntu 22.04 but the output image resolution very low:

#+HEADER: :file /media/sf_work/demo.jpg 
#+HEADER: :results file graphics
#+HEADER: :headers '("\\usepackage{tikz}") 
#+HEADER: :fit yes :imagemagick yes :imoutoptions -geometry 800 :iminoptions -density 300 :iminoptions -background white :iminoptions -alpha remove
#+begin_src latex
\begin{tikzpicture}[scale=5]
  \draw node[circle, draw] (a) {$a$}
        node[circle, draw, right of = a] (b) {$b$}
        node[circle, draw, below of = a] (c) {$c$}
        node[circle, draw, below of = b] (d) {$d$};
\end{tikzpicture}
#+end_src

Output:

Answer 1

Try the following:

#+HEADER: :fit yes :imagemagick yes :imoutoptions -geometry 800 :iminoptions -density 300 -background white -alpha remove

If you have multiple :iminoptions, the last one wins and the earlier ones are ignored. You need to combine them in a single :iminoptions header.

You can check what the src block will see using the function org-babel-get-src-block-info. This is not a command, so you cannot run it with M-x ..., you need to say M-: (org-babel-get-src-block-info). It's also not documented in the manual, so it is somewhat hidden, but it is a valuable diagnostic aid, so it's worth remembering.

When you run it with your original three setting for :iminoptions it says (I've reformatted the output a bit to make it easier to read):

("latex" "\\begin{tikzpicture}[scale=5]
  \\draw node[circle, draw] (a) {$a$}
        node[circle, draw, right of = a] (b) {$b$}
        node[circle, draw, below of = a] (c) {$c$}
        node[circle, draw, below of = b] (d) {$d$};
\\end{tikzpicture}" 
((:colname-names) (:rowname-names) (:result-params "graphics" "file" "replace") 
(:result-type . value) (:results . "graphics file replace") (:exports . "results") 
(:file . "/tmp/demo.jpg") (:headers "\\usepackage{tikz}") 
(:iminoptions . "-alpha remove") 
(:imoutoptions . "-geometry 800") 
(:imagemagick . "yes") (:fit . "yes") (:tangle . "no") 
(:hlines . "no") (:noweb . "no") (:cache . "no") (:session . "none")) "" nil 575 "(ref:%s)")

As you can see, the other two :iminoptions headers are not present.

If you run it with the modified version I show above, it says:

...
(:iminoptions . "-density 300 -background white -alpha remove")
...