include "core/components/directresize/elements/plugins/plugin.directresize.php";
include MODX_CORE_PATH."components / directresize / elements / plugins / plugin.directresize.php";
It would appear DirectResize is not currently supported (https://github.com/modxcms/revolution/issues/11630#issue-37173621). You might try using pThumb instead with your lightbox of choice.