Switch chapter header images - part 2

Question

This question is building from the elegant solution posted here.

I wanted to be able to control the size (scale) of the even and odd images in the header also.

Is something like this possible (?):

\headimages{example-image}[scale = 0.5]{example-image-a}[scale = 0.7]?

Thanks!

Here is the original solution:

\documentclass[11pt,a4paper]{book}
\usepackage{calc}
\usepackage[left=1.5cm, right=1.5cm, bindingoffset=1.5cm, headheight=120pt, top={120pt+10mm}]{geometry}
\usepackage{fancyhdr}
\usepackage{titlesec}
\usepackage{tikz}
\usepackage{lipsum}
\usepackage{fourier}
\usepackage{etoolbox}
\patchcmd{\chapter}{\thispagestyle{plain}}{\thispagestyle{fancy}}{}{}

\definecolor{gmitblue}{RGB}{93,138,168}
\definecolor{line}{RGB}{70,160,216}

\usetikzlibrary{calc}
\renewcommand{\headrulewidth}{0pt}
\newcommand\hdheight{1in}
\newcommand\ftheight{.5in}

\newsavebox\headimageodd
\newsavebox\headimageeven
\newcommand*{\headimages}[3][]{%
  % #1 - optional argument added to the optional argument of both \includegraphics
  % #2 - name of even/left side page head image
  % #3 - name of odd/right side page head image
  \savebox{\headimageeven}{%
    \includegraphics[height=120pt,#1]{#2}%
  }%
  \savebox{\headimageodd}{%
    \includegraphics[height=120pt,#1]{#3}%
  }%
}
\headimages{example-image-b}{example-image-a}

\pagestyle{fancy}
\fancyhf{}
\fancyhead[O]{%
  \begin{tikzpicture}[overlay, remember picture]%
    \fill[gmitblue] (current page.north west) rectangle ($(current page.north east)+(0,-\hdheight)$);
    \draw[line] ([yshift=-\hdheight]current page.north west) -- ([yshift=-\hdheight]current page.north east);
    \ifnum\value{chapter}=0
      \node[anchor=south west, text width=11.5cm, text=white, font=\fontsize{.7cm}{1.5cm}\selectfont\bfseries]  at ($(current page.north west)+(.5\hdheight,-\hdheight)$) {\raggedleft\rightmark};
    \else
      \node[anchor=south west, text width=2cm, text=white, font=\fontsize{2cm}{1.5cm}\selectfont\bfseries] (oddpagenum) at ($(current page.north west)+(.5\hdheight,-\hdheight)$) {\thechapter};
      \node[anchor=south west, text width=11.5cm, text=white, font=\fontsize{.5cm}{1.5cm}\selectfont\bfseries] (chapter) at (oddpagenum.south east) {\quad TOPIC TO BE DISCUSSED};
    \fi
    \node[anchor=north east, inner xsep=5mm] at (current page.north east) {\usebox\headimageodd};
  \end{tikzpicture}%
}
\fancyhead[E]{%
  \begin{tikzpicture}[overlay, remember picture]%
    \fill[gmitblue] (current page.north west) rectangle ($(current page.north east)+(0,-\hdheight)$);
    \draw[line] ([yshift=-\hdheight]current page.north west) -- ([yshift=-\hdheight]current page.north east);
    \node[anchor=south east, text width=7cm, text=white, font=\fontsize{.7cm}{1.5cm}\selectfont\bfseries] (evenpagenum) at ($(current page.north east)+(-.5\hdheight,-\hdheight)$) {\raggedleft\rightmark};
    \node[anchor=north west, inner xsep=5mm] at (current page.north west) {\usebox\headimageeven};
  \end{tikzpicture}%
}
\fancyfoot[CE]{
  \begin{tikzpicture}[overlay, remember picture]%
    \fill[gmitblue] (current page.south west) rectangle ($(current page.south east)+(0,.5in)$);
    \node[anchor=south west, text=white, font=\Large\bfseries, minimum size=.5in] at (current page.south west) {\thepage};
    \node[anchor=south, text=white, font=\large, minimum size=.5in] at (current page.south) {\leftmark};
    \node[anchor=south east, text=white, font=\large, minimum size=.5in, inner xsep=5mm] at (current page.south east) {\today};
  \end{tikzpicture}%
}
\fancyfoot[CO]{
  \begin{tikzpicture}[overlay, remember picture]%
    \fill[gmitblue] (current page.south west) rectangle ($(current page.south east)+(0,.5in)$);
    \node[anchor=south west, text=white, font=\large, minimum size=.5in, inner xsep=5mm] at (current page.south west) {\today};
    \node[anchor=south, text=white, font=\large, minimum size=.5in] at (current page.south) {\leftmark};
    \node[anchor=south east, text=white, font=\Large\bfseries, minimum size=.5in] at (current page.south east) {\thepage};
  \end{tikzpicture}%
}

\title{A reasonably long title}
\date{\today}
\author{The author}

\titleformat{\chapter}[display]
{\normalfont\huge\bfseries}{}{0pt}{\Huge}
\titlespacing*{\chapter} {0pt}{20pt}{40pt}

\begin{document}
\maketitle
\tableofcontents
\listoffigures

\chapter{Problem 1}
\headimages{example-image-c}{example-image}
\section{Problem 1}
\lipsum[1]

\section{Solution 1}
\lipsum
\lipsum

\chapter{Problem 2}
\headimages{example-image-a}{example-image-b}
\section{Problem 2}
\lipsum[1]


\end{document}

Answer 1

Without any modification of the original code I suggest using the advantages of xparse to define the command \headings

\usepackage{xparse}
\NewDocumentCommand{\headimages}{m O{height=120pt} m O{height=120pt}}{%
  % #1 - mandotory argument: first image
  % #2 - optional argument for first image
  % #3 - mandotory argument: second image
  % #4 - optional argument for second image
  \savebox{\headimageeven}{%
    \includegraphics[#2]{#1}%
  }%
  \savebox{\headimageodd}{%
    \includegraphics[#4]{#3}%
  }%
}

Usage:

\headimages{e{<first image name>}[<options first image>]{<second image name>}[<options second image>]