YouTube thumbnail preview

Shows your thumbnail with the video title beside it, at the proportions of a search result — which is where the decision to click is actually made.

A thumbnail is designed at 1280 × 720 and judged at roughly 168 pixels wide in a mobile search result. That gap is why so many thumbnails fail: text sized to look right in the editor is unreadable where it counts, and a busy composition becomes a smear. Three or four large words is the ceiling. The title matters alongside it and is cut around 60 characters, so thumbnail and title should say different things rather than repeating each other — repeating the title in the thumbnail wastes the one piece of extra information you get to show.