I received the below warning when running initImageData.php. It seems to have worked fine, but a note should be added on the Configuration section explaining how to use maintenance/run.php (or if it's safe to simply ignore this warning).
C:\inetpub\wwwroot\mediawiki\extensions\PageImages\maintenance>php initImageData.php ******************************************************************************* NOTE: Do not run maintenance scripts directly, use maintenance/run.php instead! Running scripts directly has been deprecated in MediaWiki 1.40. It may not work for some (or any) scripts in the future. ******************************************************************************* 35 done
I'm not sure if this needs to be updated in the extension code itself.