Board Thread:Support Requests - Getting Technical/@comment-1504358-20190924145312/@comment-27958705-20190924162849

WordmarkImageName = 'Wiki-wordmark.png'; BackgroundImageName = 'Wiki-background'; CommunityHeaderBackgroundImageName = 'Community-header-background'; FaviconImageName = 'Favicon.ico'; this is all images, that themedesigner uses, according to github

but your wiki might have "unused" images, that not part of software at all, like images, that were uploaded for chat icons (mediawiki:emoticons) or any other images, that has been linked via direct url.

i'd suggest to delete all unused, then restore, when you do face some lost image.