Usando bmargin para remover espaços em branco

Question

eu interpretoessecomo me dizendo que bmarginé isso que remove o espaço em branco entre a parte inferior do documento e as figuras inferiores. Mas se você executar o código verá que o espaço em branco ainda está lá, o que estou fazendo de errado?

EDIT: Acabei de notar que a segunda página tinha arquivos bmargin=0. Como faço para que isso funcione também na primeira página?

EDIT2 (resposta ao comentário): A razão pela qual uso isso em particular voffseté apenas para fazer com que pareça um pouco mais centralizado, idealmente eu gostaria de controlar o exato voffsete bmarginna primeira página, parece que posso fazer isso em todas as outras páginas, mas não o primeiro.

\documentclass{article}
\usepackage{graphicx}
\usepackage{subcaption}
\usepackage[margin=0pt, paperheight=830pt, voffset=60pt, bmargin=0pt]{geometry}
\pagestyle{empty}

\begin{document}

\begin{figure}[h]
    \centering
    \includegraphics[width=0.6\linewidth]{example-image-a}
    \label{fig:my_label}
\end{figure}
\begin{figure}[h]
    \begin{subfigure}{.5\textwidth}
        \centering
        \includegraphics[width=0.7\linewidth]{example-image-a}
        \label{fig:numberthree}
    \end{subfigure}
    \begin{subfigure}{.5\textwidth}
        \centering
        \includegraphics[width=0.7\linewidth]{example-image-b}
        \label{fig:numberfour}
    \end{subfigure}
    \label{fig:pics2}
\end{figure}
\begin{figure}[h]
\begin{subfigure}{.5\textwidth}
    \centering
    \includegraphics[width=0.7\linewidth]{example-image-a}
    \label{fig:numberthree}
\end{subfigure}
\begin{subfigure}{.5\textwidth}
    \centering
    \includegraphics[width=0.7\linewidth]{example-image-b}
    \label{fig:numberfour}
\end{subfigure}
\label{fig:pics2}
\end{figure}

\end{document}

EDITAR3:Este código é para minha resposta no comentário

\documentclass{article}
\usepackage{graphicx}
\usepackage{subcaption}
\usepackage[margin=0pt, paperheight=830pt, voffset=20pt, bmargin=50pt]{geometry}
\pagestyle{empty}

\begin{document}

\begin{figure}[h]
    \centering
    \includegraphics[width=0.5\linewidth]{example-image}
    \label{fig:my_label}
\end{figure}
\begin{figure}[h]
    \begin{subfigure}{.5\textwidth}
        \centering
        \includegraphics[width=0.7\linewidth]{example-image}
        \label{fig:numberthree}
    \end{subfigure}
    \begin{subfigure}{.5\textwidth}
        \centering
        \includegraphics[width=0.7\linewidth]{example-image}
        \label{fig:numberfour}
    \end{subfigure}
    \label{fig:pics2}
\end{figure}
\vspace*{\fill}
\begin{figure}[h]
\begin{subfigure}{.5\textwidth}
    \centering
    \includegraphics[width=0.7\linewidth]{example-image}
    \label{fig:numberthree}
\end{subfigure}
\begin{subfigure}{.5\textwidth}
    \centering
    \includegraphics[width=0.7\linewidth]{example-image}
    \label{fig:numberfour}
\end{subfigure}
\label{fig:pics2}
\end{figure}
\begin{figure}[h]
\begin{subfigure}{.5\textwidth}
    \centering
    \includegraphics[width=0.7\linewidth]{example-image}
    \label{fig:numberthree}
\end{subfigure}
\begin{subfigure}{.5\textwidth}
    \centering
    \includegraphics[width=0.7\linewidth]{example-image}
    \label{fig:numberfour}
\end{subfigure}
\label{fig:pics2}
\end{figure}
\begin{figure}[h]
\begin{subfigure}{.5\textwidth}
    \centering
    \includegraphics[width=0.7\linewidth]{example-image}
    \label{fig:numberthree}
\end{subfigure}
\begin{subfigure}{.5\textwidth}
    \centering
    \includegraphics[width=0.7\linewidth]{example-image}
    \label{fig:numberfour}
\end{subfigure}
\label{fig:pics2}
\end{figure}\begin{figure}[h]
\begin{subfigure}{.5\textwidth}
    \centering
    \includegraphics[width=0.7\linewidth]{example-image}
    \label{fig:numberthree}
\end{subfigure}
\begin{subfigure}{.5\textwidth}
    \centering
    \includegraphics[width=0.7\linewidth]{example-image}
    \label{fig:numberfour}
\end{subfigure}
\label{fig:pics2}
\end{figure}
\begin{figure}[h]
\begin{subfigure}{.5\textwidth}
    \centering
    \includegraphics[width=0.7\linewidth]{example-image}
    \label{fig:numberthree}
\end{subfigure}
\begin{subfigure}{.5\textwidth}
    \centering
    \includegraphics[width=0.7\linewidth]{example-image}
    \label{fig:numberfour}
\end{subfigure}
\label{fig:pics2}
\end{figure}

\end{document}

Answer 1

Experimente isto:

\documentclass{article}
\usepackage{graphicx}
\usepackage{subcaption}
\usepackage[paperheight=830pt, margin=0pt, noheadfoot]{geometry}
\pagestyle{empty}

\makeatletter
\@fptop=0pt% distance from top of text area to first [p] figure
\@fpbot=0pt% distance from bottom of text area to last [p] figure.
\makeatother

\begin{document}
\begin{figure}[p]
    \centering
    \includegraphics[width=0.6\linewidth]{example-image-a}
    \label{fig:my_label}
\end{figure}
\begin{figure}[p]
    \begin{subfigure}{.5\textwidth}
        \centering
        \includegraphics[width=0.7\linewidth]{example-image-a}
        \label{fig:numberthree}
    \end{subfigure}
    \begin{subfigure}{.5\textwidth}
        \centering
        \includegraphics[width=0.7\linewidth]{example-image-b}
        \label{fig:numberfour}
    \end{subfigure}
    \label{fig:pics2}
\end{figure}
\begin{figure}[p]
\begin{subfigure}{.5\textwidth}
    \centering
    \includegraphics[width=0.7\linewidth]{example-image-a}
    \label{fig:numberthree}
\end{subfigure}
\begin{subfigure}{.5\textwidth}
    \centering
    \includegraphics[width=0.7\linewidth]{example-image-b}
    \label{fig:numberfour}
\end{subfigure}
\label{fig:pics2}
\end{figure}
\end{document}