Clear the page after an itemize or enumerate, but only if it's the outermost one

Question

I'm working on a technical document in which each page has an image followed by a list of information/actions in an itemize or enumerate environment. I'd like to make sure that the page is cleared after each such list, without inserting manual \clearpage commands. What's the best way to redefine the itemize/enumerate environments so that they run \clearpage? One difficulty is that there can be nested lists, and I only want to clear the page after the outermost list ends.

For example:

\documentclass{article}
\usepackage{graphicx}
\begin{document}
\includegraphics[width=\textwidth]{image1.png}
\begin{enumerate}
    \item First item
    \item Second item
        \begin{enumerate}
        \item Sub-list 1
        \item Sub-list 2
        \end{enumerate}
    \item Third item
\end{enumerate}

\includegraphics[width=\textwidth]{image2.png}
...

Actually, the pics are included using figure commands with the [t] flag. The issue I'm having is if the list is very short, then the next list starts on the same page, rather than following on from the image on the next page.

Answer 1

I would use the enumitem package and and create a new list type, writing something like this in the preamble (supposing you'll have at most 3 levels):

\usepackage{enumitem}
\newlist{info}{enumerate}{3}
\setlist[info,1]{after=\clearpage}

This way, each first level info list ends up in a \clearpage. In the arguments of \setlist, of course, you can add other specifications as to formatting labels, list layout, &c.

Answer 2

I managed to find the answer to this myself, and somebody else might find this useful. Since I didn't want to change the environment used (as in @Bernard's answer) a change to how enumerate worked was needed. In the latex source I found how the environment is defined, and this was my solution:

\makeatletter
\newcommand\myendenum{%
    \ifnum \@enumdepth > 1%
        \endlist%
    \else%
        \endlist\clearpage%
    \fi}
\let\endenumerate\myendenum
\makeatother

The check on \@enumdepth makes sure that sub-lists don't break. My first guess was to compare with 0, but 1 worked as I wanted.