Download image PDF from R Shiny using R Markdown

Hi, I am hosting a Shiny app on shinyapps.io. In the Shiny app, I included a download button which can download a PDF document based on the inputs in the app. I have created an R Markdown file with codes written in LaTex language for the PDF. The codes work fine (I was able to use the shiny app and download a nice PDF document), until I tried to include an image in the R markdown file (I want to put a logo in the PDF).

This is the code that I added to my R markdown preamble:

header-includes:
-usepackage{graphicx}

and then I added the image in the middle of my document with the code:

\begin{center}\includegraphics[width=9cm]{logo}\end{center}

I am able to view the PDF with the image when I knit it from R Studio, however it does not work when I host it on shinyapps.io.

Please help!!

Is logo a file that is available in the Shiny environment?