(see below for my first answer)
Edit: A more complete and customizable solution (using columns to put images on the left or on the right).

\documentclass{beamer}
\usepackage{tikz}
\usepackage{calc}
\usepackage{lipsum}
% put a node on absolute position on the page
% (two compilations is necessary to get a good placement)
% #1: anchor of the page
% #2: shift vector
% #3: anchor of the node
% #4: minimum height of the node
% #5: minimum width of the node
% #6: content
\newcommand\absoluteput[6]{%
\begin{tikzpicture}[overlay,remember picture]
\path (current page.#1) ++ (#2)
node[#3,minimum height=#4,minimum width=#5]{#6};
\end{tikzpicture}%
}
% put a node 5mm above the south of the page
% #1: min height
% #2: content
\newcommand\putbottom[2]{\absoluteput{south}{0,5mm}{above}{#1}{0}{#2}}
% put a node 5mm to the left of the east of the page
% #1: min width
% #2: content
\newcommand\putright[2]{\absoluteput{east}{-5mm,0}{left}{0}{#1}{#2}}
% put a node 5mm to the right of the west of the page
% #1: min width
% #2: content
\newcommand\putleft[2]{\absoluteput{west}{5mm,0}{right}{0}{#1}{#2}}
\begin{document}
\begin{frame}{Frame with images at bottom}
\begin{itemize}[<+->]
\item Pellentesque interdum sapien sed nulla.
\putbottom{42mm}{\includegraphics<.>[height=40mm]{example-image}}
\item Proin tincidunt.
\putbottom{42mm}{\includegraphics<.>[height=30mm]{example-image-a}}
\item Aliquam volutpat est vel massa.
\putbottom{42mm}{\includegraphics<.>[height=20mm]{example-image}}
\item Sed dolor lacus, imperdiet non, ornare non, commodo eu,
neque. Integer pretium semper justo.
\putbottom{42mm}{\includegraphics<.>[height=42mm]{example-image-a}}
\end{itemize}
\vfill
\vspace*{47mm} % 5mm (margin) + 42mm (max height of images)
\end{frame}
\begin{frame}{Frame with images on the right}
\begin{columns}
\column{\linewidth-5mm-47mm} % \linewidth - (margin) - (max width of images)
\begin{itemize}[<+->]
\item Pellentesque interdum sapien sed nulla.
\putright{47mm}{\includegraphics<.>[width=40mm]{example-image}}
\item Proin tincidunt.
\putright{47mm}{\includegraphics<.>[width=30mm]{example-image-a}}
\item Aliquam volutpat est vel massa.
\putright{47mm}{\includegraphics<.>[width=20mm]{example-image}}
\item Sed dolor lacus, imperdiet non, ornare non, commodo eu,
neque. Integer pretium semper justo.
\putright{47mm}{\includegraphics<.>[width=47mm]{example-image-a}}
\item Proin tincidunt.
\putright{47mm}{\includegraphics<.>[width=30mm]{example-image-a}}
\item Aliquam volutpat est vel massa.
\putright{47mm}{\includegraphics<.>[width=20mm]{example-image}}
\item Sed dolor lacus, imperdiet non, ornare non, commodo eu,
neque. Integer pretium semper justo.
\putright{47mm}{\includegraphics<.>[width=42mm]{example-image-a}}
\end{itemize}
\column{47mm} % (max width of images)
\end{columns}
\end{frame}
\begin{frame}{Frame with images on the left}
\begin{columns}
\column{30mm} % (max width of images)
\column{\linewidth-5mm-30mm} % \linewidth - (margin) - (max xidth of images)
\begin{itemize}[<+->]
\item Pellentesque interdum sapien sed nulla.
\putleft{30mm}{\includegraphics<.>[angle=90,width=30mm]{example-image}}
\item Proin tincidunt.
\putleft{30mm}{\includegraphics<.>[width=30mm]{example-image-a}}
\item Aliquam volutpat est vel massa.
\putleft{30mm}{\includegraphics<.>[width=20mm]{example-image}}
\item Sed dolor lacus, imperdiet non, ornare non, commodo eu,
neque. Integer pretium semper justo.
\putleft{30mm}{\includegraphics<.>[width=30mm]{example-image-a}}
\item Proin tincidunt.
\putleft{30mm}{\includegraphics<.>[width=30mm]{example-image-a}}
\item Aliquam volutpat est vel massa.
\putleft{30mm}{\includegraphics<.>[width=30mm]{example-image}}
\item Sed dolor lacus, imperdiet non, ornare non, commodo eu,
neque. Integer pretium semper justo.
\putleft{30mm}{\includegraphics<.>[width=16mm]{example-image-a}}
\end{itemize}
\end{columns}
\end{frame}
\end{document}
First answer:
You can use TikZ to add a picture at absolute place and you can use the option <+->
with itemize
to use incremental overlay specifications. I add calls to vfill
and \vspace...
to keep space for the images.
You can make

Here, the code:
\documentclass{beamer}
\usepackage{tikz}
% put a node 5mm above the bottom of the page
% (two compilations required to get a good placement)
\newcommand\myabsoluteplace[1]{%
\begin{tikzpicture}[overlay,remember picture]
\node[anchor=south] at ([yshift=5mm]current page.south) {#1};
\end{tikzpicture}%
}
\begin{document}
\begin{frame}{title}
\begin{itemize}[<+->]
\item text 1 \myabsoluteplace{\includegraphics<.>[height=40mm]{example-image}}
\item text 2 \myabsoluteplace{\includegraphics<.>[height=30mm]{example-image-a}}
\item text 3 \myabsoluteplace{\includegraphics<.>[height=20mm]{example-image}}
\item text 4 \myabsoluteplace{\includegraphics<.>[height=42mm]{example-image-a}}
\end{itemize}
\vfill
\vspace*{47mm} % 5mm (margin) + 42mm (max images)
\end{frame}
\end{document}