[Tex/LaTex] Produce cards with a PNG background for each card

Question

I need to produce 50 playing cards (60x90mm) with a template available in PSD or PNG or anything else (see picture below).

Here is what I tried:

\documentclass{minimal}
\usepackage[paperheight=6cm,paperwidth=9cm]{geometry}
\usepackage{graphicx}

\newcommand{\card}{
\centerline{\includegraphics{background.png}} % Why isn't it locked on top-left corner 
                                              % of the  page ? (it should)
% How to insert the text here, vertically + horizontally centered over the background?
\newpage
}

\begin{document}
\card{This is card 1.}
\card{Hello mister polynomial $x^2+1$.}

\end{document}

Questions:

1. What file format to use for the background template? Would you use PNG? (Goal: I'm producing a PDF that will go to the print worker.)

2. Why doesn't the previous solution overwrite the text over the background? (this is what should happen)?

---

Bad output (with previous code):

Answer 1

Update at the end -- give it a try

The background image can be done with tcolorbox and using many of its options, putting it in the background. See the applications of the options how the image is changed.

Considering the dimensions: Please take into account the cutting by your printer, so the margins should be larger, most likely!

\documentclass{article}

\usepackage[paperwidth=50mm,paperheight=90mm,margin=0pt,nohead,nofoot]{geometry}

\usepackage{blindtext}
\usepackage[most]{tcolorbox}

\newtcolorbox[auto counter]{cardbox}[1][]{enhanced,nobeforeafter,after={\clearpage},width=50mm,height=90mm,halign=center, valign=center, title={This is card \thetcbcounter},colback={white!70!yellow},colbacktitle={cyan},coltitle={black},overlay={%
    \begin{tcbclipinterior}
    \node[opacity=0.2] (A) at (interior.center) {\includegraphics[width=5cm,height=9cm]{ente}};
    \end{tcbclipinterior}
  },#1}

\parindent=0pt

\newcommand{\card}[2][]{%
  \begin{cardbox}[#1]
    #2%
  \end{cardbox}%
}
\begin{document}
\pagestyle{empty}

\card{Hello Darkness my old friend}

\card[fontupper=\huge]{Hello Mr. Polynomial $x^{2} + x = 1$}

\end{document}

\documentclass{article}

\usepackage[paperwidth=150mm,paperheight=270mm,margin=0pt,nohead,nofoot]{geometry}



\usepackage{blindtext}
\usepackage[most]{tcolorbox}

\tcbset{cardsboxstyle/.style={%
    left skip=0em,
    right skip=0em,
    width=50mm,
    height=90mm,
    halign=center, 
    valign=center,
    title={This is card \thetcbcounter},
    left=0pt,
    right=0pt,
    top=0pt,
    bottom=0pt,
    colback={white!70!yellow},
    colbacktitle={cyan},
    coltitle={black}
  },
  backgroundimage/.style={%
    overlay={%
    \begin{tcbclipinterior}
    \node[opacity=0.1] (A) at (interior.center) {\includegraphics[width=5cm,height=9cm]{ente}};
    \end{tcbclipinterior}
    }
  }
}


\newtcolorbox[auto counter]{cardbox}[1][]{enhanced,nobeforeafter,cardsboxstyle,backgroundimage,#1}

\parindent=0em

\newcommand{\card}[2][]{%
  \begin{cardbox}[#1]
    #2%
  \end{cardbox}%
}
\begin{document}
\pagestyle{empty}


\begin{tcbraster}[raster columns=3,raster column skip=0pt,raster row skip=0pt,raster width=150mm,raster equal height,raster left skip=0pt,raster right skip=0pt]
\card{Hello Duckness my old friend}
\card[fontupper=\huge]{Hello Mr. Polynomial $x^{2} + x = 1$}
\card{Hello Cuteness my old friend}
\card[colbacktitle={red},overlay={\draw[opacity=0.2,step=1cm,help lines,blue] (interior.north east) grid (interior.south west);}]{Hello Cuteness my old friend}
\card{Hello Duckness my old friend}
\card[fontupper=\huge]{Hello Mr. Polynomial $x^{2} + x = 1$}
\card{Hello Cuteness my old friend}
\card{Hello Duckness my old friend}
\card[colupper={blue},ams align]{E=mc^{2}}
\end{tcbraster}

\end{document}