The example in the question has two
documentclass commands, which is not allowed in LaTeX. You can use a single command with the
convert option added to the options of the first line.
Note that the second
2pt option does not do anything, it generates a warning and it can be removed. Note also that you need to run LaTeX with the
shell-escape option to allow calling
convert. I don't use TeXstudio myself but according to How to invoke latex with the -shell-escape flag in TeXMakerX? you can do it in various ways, one of which is to add a compile directive at the start of the file as in the example below.
% !TeX TXS-program:compile = txs:///pdflatex/[--shell-escape]
\Huge converted pdf
Result (note that the squares indicate transparency, they are shown because they are invisible):
Apart from the
.pdf is also generated automatically.