There are a couple of options, depending on what yo're after exactly:

\documentclass{article}
\usepackage{graphicx}
\setcounter{topnumber}{3}% Just for this example
\begin{document}
\listoffigures
\begin{figure}
\addcontentsline{lof}{figure}{Example image A}%
\centering
\includegraphics[height=4\baselineskip]{example-image-a}
Example image A
\end{figure}
\begin{figure}
\addcontentsline{lof}{figure}{\protect\numberline{}Example image B}%
\centering
\includegraphics[height=4\baselineskip]{example-image-b}
Example image B
\end{figure}
\begin{figure}
\centering
\includegraphics[height=4\baselineskip]{example-image-c}
\caption{Example image C}
\end{figure}
\end{document}
The figure caption is added using \addcontentsline{lof}{figure}{<caption>}
, where <caption>
can either contain a blank \numberline{}
, or just the regular caption. The above example shows the usage of either.
It would also be possible to have no label shows in the image, but have a numbered entry in the LoF using caption
. But it would seem strange to have a numbered entry in the LoF and an unnumbered figure.