Video thumbnails
Choose a moment that explains the video at a glance. Brightness or detail alone is not enough: the frame should show the subject, action, or result the viewer came to see.
Find candidate moments
Sample the video across its duration. Skip empty frames, transition frames, motion blur, and the first or last instant unless they were designed as covers. Select a small set of visually distinct candidates and show them together with timestamps. Favor frames with clear subjects, good contrast, readable text, and enough space for a title when a title is needed.
Treat automatic scoring as a shortlist. Inspect the candidates and choose the frame that tells the story. Let the user choose when several candidates represent meaningfully different messages.
Make each aspect ratio
Create only the ratios needed for the destination. Reframe each one independently. Keep faces, controls, text, and product edges intact; extend the background or use a designed layout if a crop would remove essential information.
If the original video is generated from a composition, render the selected moment directly from that composition at each target size. For ordinary footage, extract a high-quality frame and crop or compose it carefully. Check the final image at phone size.
Animated covers
When requested, choose a short moment with gentle motion and similar start and end frames. Trim to a natural loop point or use a brief crossfade if it does not duplicate a moving subject. Keep the file small enough for the destination. Check the seam by watching several repeats; a duplicate hand, pointer, or object is a bad loop even if a pixel metric looks acceptable.
Deliver clearly named files with format and timestamp or selection noted. Verify every still and loop opens, fits its dimensions, and represents the video faithfully.