A thumbnail can look polished at full size and still become a blur in a crowded feed. The usual culprit is competition: too many subjects, background details, or visual effects asking for attention at once. Give the prompt one focal point and let everything else support it.
Decide what reads first
Choose the single object or face that should lead the composition, then describe its placement and scale. A close-up of a cracked ceramic mug against a dark counter reads differently from a wide kitchen scene where the mug is one detail among many. For a story thumbnail, a tilted object or a strong shadow can suggest tension without filling the frame with clues.
Use contrast, not clutter
Specify a separation between the subject and background: warm light against a cool wall, a bright silhouette against a dim room, or a clean edge of negative space. Ask for a simple background when the subject already carries the idea. If text will be added later, leave a clear area for it instead of asking the image prompt to create finished lettering.
Check the small version
Before refining tiny details, view the concept at the approximate size it will appear in a feed. If the subject no longer stands out, adjust the crop, contrast, or spacing first. A focused prompt gives you a stronger starting composition; you can then adapt its colors and details to the channel and story.
