Grâce aux remarques de @touhami, et l'option `valign=t` de l'extension [adjustbox](https://www.ctan.org/pkg/adjustbox), qui aligne précisément la figure avec le haut de la ligne supérieure, j'ai corrigé mon ECM, qui fonctionne désormais : \documentclass[a4paper, 12 pt, showframe, french]{scrartcl} \usepackage[utf8x]{inputenc} \usepackage[T1]{fontenc} \usepackage[light, largesmallcaps]{kpfonts} \usepackage{mwe} \usepackage{geometry} \usepackage{lipsum} \usepackage{microtype} \usepackage{grid-system} \usepackage[Export]{adjustbox} \usepackage{babel} \begin{document} \begin{row}{4}{2} \begin{cell}{3} \lipsum[1] \end{cell} \begin{cell}{1} {\centering \includegraphics[keepaspectratio = true, width = \textwidth, valign=t]{example-image-a}} \end{cell} \end{row}\\ \begin{row}{1}{1} \begin{cell}{1} \raisebox{-\totalheight}{\centering \includegraphics[keepaspectratio = true, width = \textwidth]{example-image-a}} \end{cell} \end{row}\\ \begin{row}{1}{1} \begin{cell}{1} \raisebox{-\totalheight}{\centering \includegraphics[keepaspectratio = true, width = \textwidth]{example-image-b}} \end{cell} \end{row} \end{document}

Grâce aux remarques de @touhami, j'ai corrigé mon ECM, qui fonctionne désormais : \documentclass[a4paper, 12 pt, showframe, french]{scrartcl} \usepackage[utf8x]{inputenc} \usepackage[T1]{fontenc} \usepackage[light, largesmallcaps]{kpfonts} \usepackage{mwe} \usepackage{geometry} \usepackage{lipsum} \usepackage{microtype} \usepackage{grid-system} \usepackage{babel} \begin{document} \begin{row}{4}{2} \begin{cell}{3} \lipsum[1] \end{cell} \begin{cell}{1} \raisebox{-\totalheight}{\centering \includegraphics[keepaspectratio = true, width = \textwidth]{example-image-a}} \end{cell} \end{row}\\ \begin{row}{1}{1} \begin{cell}{1} \raisebox{-\totalheight}{\centering \includegraphics[keepaspectratio = true, width = \textwidth]{example-image-b}} \end{cell} \end{row} \end{document}