Why exclude infoboxes? The "image" parameter could be used.
Topic on Talk:Growth/Personalized first day/Structured tasks/Add an image
We exclude articles that already have infoboxes.
Understanding which infobox parameter to use for each language would be too complicated. We have to identify where to place the image, and also where to place the caption.
Plus, we have more and more wikis using Wikidata infoboxes. In this case, when you edit the source of the article, you have no idea if an image is already in the infobox.