Guide · 11 lessons
Learn: short guides to thumbnails, captions and chapters
Short guides, three to four minutes each. Every one explains a platform rule or a design habit, says where the rule comes from, and ends with a quick check and a link to the tool that puts it into practice. Rules change often, so each guide shows the date it was last checked. Your reading progress stays in this browser only.
Get thumbnails, captions, hashtags and chapters right the first time, and know why.
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Start learningModule 1 Thumbnails and images
How thumbnails, vertical covers and profile pictures look at the sizes people actually see them.
- Mobile vs desktop: making thumbnails readable at every sizeYou design a thumbnail at 1280 pixels wide. Most people see it much smaller, partly covered, in light or dark mode.
- Safe areas for Shorts, Reels and TikTok coversVertical video is 9:16, but the app draws buttons, names and captions on top of it. Plan for the parts people can't see.
- Profile pictures that stay sharp from 800 pixels down to a tiny circleUpload a large square, frame it for a circle, and judge it at the smallest size people see.
Module 2 Captions, limits and hashtags
Where each platform counts and cuts text, what the hashtag rules really are, and how to keep your spacing.
- Character limits and where your text gets cutEvery platform has a hard limit and a much earlier point where the feed cuts your text. Write for the second one.
- Hashtag limits: YouTube's 60-tag rule and Instagram's limit of 5More hashtags isn't more reach. YouTube ignores too many, and Instagram now limits posts to five.
- Keeping line breaks and spacing in captionsEmpty lines that only hold spaces can disappear. A line that looks empty but isn't survives.
Module 3 Chapters, transcripts and tags
Chapters YouTube accepts, transcripts you can reuse, and what tags still do.
Module 4 Testing and workflows
Testing thumbnails properly, fair giveaways, one post for several platforms, and channel banners.
- Testing thumbnails properly: what YouTube's A/B test measuresA thumbnail test is only as good as what it measures and what you changed. Change one thing, and let watch time decide.
- One video, five platforms: adapting a post without starting overKeep the idea, change the format: frame, length, text limits and hashtag rules differ on each platform.
- YouTube channel banners: the safe area from TV to phoneUpload 2048×1152 or larger, but put everything that matters inside the central safe area.
Platform rules change often. Each guide shows the date it was last checked; when in doubt, the platform's own help page has the final word.
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