I am trying to create a figure with subfigures aligned both horizontally and vertically in the same figure to explain this better i attached a primitive drawing.
The labels are not of importance in which order they come i just cant seem to figure out how to place the (f) and (g) images on top of (d) and (e) in the same
\begin{figure}
...
\end{figure}
One way to do this is to box each column up in a minipage, and provide a minipage for each subimage in the last column. You can then include the \subcaption inside each of the minipages. Here is an example following your layout, but just using text instead of the images:
\documentclass{article}
\usepackage{subcaption}
\begin{document}
\begin{figure}[htp]
\centering
\begin{minipage}[t]{0.15\linewidth}
\centering \large A
\vspace{2cm}
\large AA
\subcaption{Subfigure A}
\end{minipage}
\begin{minipage}[t]{0.15\linewidth}
\centering \large B
\vspace{2cm}
\large BB
\subcaption{Subfigure B}
\end{minipage}
\begin{minipage}[t]{0.15\linewidth}
\centering \large C
\vspace{2cm}
\large CC
\subcaption{Subfigure C}
\end{minipage}
\begin{minipage}[t]{0.15\linewidth}
\centering
\begin{minipage}[t]{0.5\linewidth}
\centering F
\subcaption{Subfigure F}
\end{minipage}
\begin{minipage}[b]{0.5\linewidth}
\centering D \subcaption{Subfigure D}
\end{minipage}
\end{minipage}
\begin{minipage}[t]{0.15\linewidth}
\centering
\begin{minipage}[t]{0.5\linewidth}
\centering G
\subcaption{Subfigure G}
\end{minipage}
\begin{minipage}[b]{0.5\linewidth}
\centering E \subcaption{Subfigure E}
\end{minipage}
\end{minipage}
\caption{Whole figure caption}
\label{fig:cap}
\end{figure}
\end{document}
