I am making a presentation in beamer and I would like to make disappear and appear some images. I am using the option \only<> but I obtain different slides like:


When I click on the ouse button it seems like I am chaning the full slides instead of only the figures appearing.
The code is :
\begin{frame}
\centering
\textbf{Noise effect}
\begin{columns}
\column{0.4\textwidth}
\begin{itemize}
\item $y_1(t)=\cos(2\pi f_1 t)$
\centering
\includegraphics[scale=0.14]{sineseriesspectrum}\\
\only<1>{\includegraphics[scale=0.7]{noiseeffectsine}}
%\transfade{\includegraphics[scale=0.7]{noiseeffectsine}}
\only<2>{\includegraphics[scale=0.7]{sineeffectresults}}
\end{itemize}
\column{0.5\textwidth}
\begin{itemize}
\item $y_2(t)=\text{white noise}$
\centering
\includegraphics[scale=0.14]{wnseriesspectrum}\\
\only<1>{\includegraphics[scale=0.7]{noiseeffectwn}}
\only<2>{\includegraphics[scale=0.7]{noiseeffectresults}}
\end{itemize}
\end{columns}
\end{frame}

ima1,...,ima7. How exactly do you want the images to appear/disappear? – Gonzalo Medina Aug 01 '14 at 16:59