\documentclass{book}
\usepackage[dvipsnames, cmyk]{xcolor}
\usepackage{tcolorbox,graphicx}
\tcbuselibrary{skins}

\setlength{\fboxrule}{0pt}

\NewTColorBox
    {notes}
    { m !O{} }  % 1: title, 2: extra options
    {
        before title*={\framebox(5mm,5mm)[c]{\includegraphics[width=4mm,height=4mm]{danger.png}}},
        title={{\bf#1}},
        coltitle=white,
        colframe=Violet,
        colback=Violet,
        coltext=white,
        #2
    }

\begin{document}

\begin{notes}{This is my title}
    This is my test callout!
\end{notes}

\end{document}