\documentclass[a4paper,11pt]{article}
\usepackage[polish]{babel}
\usepackage[utf8]{inputenc} 
\usepackage[T1]{fontenc}
\usepackage{fourier}
\usepackage{graphicx}



\begin{document}

\begin{figure}[!hbt]
\begin{minipage}[b]{0.3\textwidth}
\centering
\includegraphics[scale=0.65]{demo.pdf}
\caption{Skala 0.65}
\label{fig:demo:065}
\end{minipage}\hspace{\fill}
%
\begin{minipage}[b]{0.3\textwidth}
\centering
\includegraphics[scale=0.5]{demo.pdf}
\caption{Skala 0.5}
\label{fig:demo:05}
\end{minipage}\hspace{\fill}
%
\begin{minipage}[b]{0.3\textwidth}
\centering
\includegraphics[scale=0.35]{demo.pdf}
\caption{Skala 0.35}
\label{fig:demo:035}
\end{minipage}
\end{figure}

\end{document}