The right-side recommendation sidebar on the YouTube watch page shows thumbnails at smaller sizes than the home feed and with title text below taking 2 lines. Designs that work on the home feed sometimes fail here due to the smaller size and competing thumbnails stacked vertically.
When to use this
Use for: optimizing thumbnails to look good in the recommendation column (significant source of views for many channels), testing how your thumbnail compares against typical sidebar competitors, ensuring critical visual elements survive the size reduction.
Frequently Asked Questions
How big is the sidebar thumbnail?
Approximately 168x94 pixels on desktop, smaller on mobile (which doesn't show sidebar - shows 'up next' card instead). Source thumbnail is still 1280x720 - the browser scales down. Anti-aliasing and image quality at the source still matters for the scaled-down render.
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