A Thumbnail Prompt Needs an Idea Before It Needs Polish
This Short comes from trying to make the text and image for a YouTube thumbnail work together.
The interesting part is the prompt-building process: research the problem, describe the result, inspect what comes back, and adjust the brief. It is a workflow to experiment with, rather than a promise that one prompt will produce a finished thumbnail.
I would start by naming the video's central idea. Then ask for a few different ways to communicate it visually, with short text that supports the image instead of repeating everything.
Before polishing a direction, check whether the combination is understandable at a small size and honest about the video behind it.
A catchy option that promises a different video is not the right result. The prompt should help explore directions; choosing the one that fits is still an editorial decision.