How to add a list of figures row by row?

I tried to add a list of figures row by row but they interfere with other sections not sure how to fix.

The figures are all of the same size 6in.
Conclusion Section is interfering with the last (5th) picture, I tried bigskip, newpage, pagebreak not working.

subsubsection{Results}
begin{paragraph}
space The table ref{table:res} summarizes the results we got from the experiment.


Graphical Results (Solution Time, Speed up, Efficiency):
begin{figure}[h]
    centering
    includegraphics[width=6in]{images/100t.png}
    caption{Solution Time Vs Number of Processors M = 100}
    label{fig:100t}
end{figure}

begin{figure}[h]
    centering
    includegraphics[width=6in]{images/200t.png}
    caption{Solution Time Vs Number of Processors M = 200}
    label{fig:200t}
end{figure}

begin{figure}[h]
    centering
    includegraphics[width =6in]{images/500t.png}
    caption{Solution Time Vs Number of Processors M = 500}
    label{fig:500t}
end{figure}

begin{figure}[h]
    centering
    includegraphics[width =6in]{images/1000t.png}
    caption{Solution Time Vs Number of Processors M = 1000}
    label{fig:1000t}
end{figure}

begin{figure}[h]
    centering
    includegraphics[width=6in]{images/2000t.png}
    caption{Solution Time Vs Number of Processors M = 2000}
    label{fig:2000t}
end{figure}

end{paragraph}
pagebreak
section{Conclusion}

Thanks.