Your Shorts are open to remixing by default. Here is the YouTube Studio setting that limits it, and what YouTube Help says happens to remixes already made from your video.
YouTube says half of all channels and videos have an impressions click-through rate between 2% and 10%, and its own A/B tests now pick winners by watch time, not clicks. What YouTube says, where feed previews and Shorts reduce the thumbnail's role, what testing shows about style, and how to decide how much effort to spend.
A 2026 YouTube thumbnail might be a picked frame, a designed image or an AI draft from Ask Studio, and it is increasingly chosen by a watch-time test rather than a hunch. The official specs, three ways thumbnails get made, what changed for Shorts in July 2026, how Test & Compare picks a winner and an eight-step workflow.