How can I set the subfigure labels in latex to uppercase?

Question

I made a figure within my LaTeX document using the subfigure package, containing three subfigures. The part where the subfigures are now automatically labelled "(a)", "(b)", "(c)" need to be uppercased, though.

I.e. the result from the LaTeX code in the finally rendered PDF is

(a) img1 (b) img2 (c) img3

but it needs to be

(A) img1 (B) img2 (C) img3

How can I set this up?

The code looks something like this:

    \usepackage{subfigure}
[...]
    \begin{sidewaysfigure}[p]
        \centering
        \subfigure[image1]{
            \label{fig:img1}
            \includegraphics[scale=2]{figures/img1.png}
        }
        \subfigure[image2]{
            \label{fig:img2}
            \includegraphics[scale=2]{figures/img2.png}
        }
        \subfigure[image3]{
            \label{fig:img3}
            \includegraphics[scale=2]{figures/img3.png}
        }
        \caption[my images]{\textbf{ My images} I am referring to (A), (B) and (C) respectively.}\label{fig:imgs}\end{sidewaysfigure}

Answer 1

I didn't try this, but putting

\renewcommand{\thesubfigure}{(\Alph{subfigure})}

in your preamble should do it.

Answer 2

In answer to the new question within an answer by salmaaries, here is a tested, working version using the suggestion from AVB:

\documentclass{article}
\usepackage{graphicx}
\usepackage{subfig}
\renewcommand{\thesubfigure}{\Alph{subfigure}}
\begin{document}
    \begin{figure}[H]
        \centering
        \begin{tabular}{c}
            \subfloat[First caption]{\label{fig:figure1a}}
             \includegraphics[width=0.8\textwidth]{Figure1A}\\
             \subfloat[Second caption]{\label{fig:figure1b}}
             \includegraphics[width=0.8\textwidth]{figure1B}\\
             \subfloat[Third caption]{\label{fig:figure1c}}
            \includegraphics[width=0.8\textwidth]{figure1C}
        \end{tabular} 
    \end{figure}
\end{document}

Answer 3

To force capital letters, put the offending character in curly brackets.

\caption[my images]{\textbf{ My images} I am referring to ({A}), ({B}) and ({C}) respectively.}\label{fig:imgs}\end{sidewaysfigure}