1. Standalone informative poster
This image carries the poster's message; its alternative includes that message and its essential visual metaphor.
2. Image-only link
The thumbnail's purpose is to open the guide. Its alternative names that destination.
3. Redundant illustration beside a full text equivalent
AI Anonymous poster: Your AI graphic needs alt text. An amber paper sun in a dark picture frame unfurls into a ribbon of paper with lines suggesting text. Draft it. Check it. Add it. Full guide at jabsystems.io. From JABSystems.
The illustration below repeats the information above and has no separate action. It uses explicitly empty alt. This is a context decision, not permission to hide informative images.