Drawing a sphere and an ellipsoid in the same picture in TiKz

You can use two example images named A and B. tikzset give you the type of the arrow with the options of your size and position. The idea is taken from this link Fancy arrows with TikZ using the best code of the user @Peter Grill that I have modificated appropriately.

documentclass{article}
usepackage{tikz}
usetikzlibrary{shapes}
usepackage{graphicx}
usepackage{xcolor}
tikzset{My Arrow Style/.style={single arrow, rounded corners=1pt, fill=lightgray, anchor=center, align=center,xshift=2cm, yshift=2cm, minimum height=2cm, minimum width=2cm,text width=4cm}}
newcommand{MyArrow}[2][]{tikz[baseline={([yshift=-7ex]current bounding box.center)}] node [My Arrow Style,#1] {#2};}
begin{document}

begin{figure}
  includegraphics[width=3cm,height=5cm,keepaspectratio]{example-image-a}
  MyArrow{Affine trasformation}
  includegraphics[width=3cm,height=5cm,keepaspectratio]{example-image-b}
end{figure}

end{document}