I think most top YouTubers are considered "creators" more than "influencers". It takes a substantially different set of skills to create videos people want to watch than photos people want to view, and intuitively you'd expect the latter to tilt more towards first-impression attractiveness. Instagram fits more closely with the way this guy used his Twitter account (pictures and text), I can't seem to find an authoritative list of independently-famous Instagram influencers, but the lists I've seen consist primarily of models.