JPEG images changed to black and white

Question

All my jpg images in LaTeX are coming out in black and white. Similar question here, but it doesn't seem to answer my question. I am using Texmaker and latex + dvips + sp2pdf + ViewPDF

Here is an example of my code:

 \documentclass[12pt,oneside,openany,a4paper,%..... Layout
           afrikaans, english,%.............. Global language selection
           ]{memoir}
 \usepackage{babel}%.............................. Language setup
\usepackage{graphicx}%........................... Graphicx loaded in usthesis


\begin{document}
\begin{figure}[!htb]
\centering
\includegraphics[width=0.8\textwidth,natwidth=831,natheight=812]{FourHeliostatsTry3.jpg}
\caption{Intersection and transformation of four heliostats}
\label{Ffourheliostats}
\end{figure}
\end{document}