Stable Diffusion XL generates absolutely cool images for my autoblogs with these very simple prompts:
1.
A highly realistic image for a blog article on topic of "%post_title%" - works best for "photographic" style preset.
2.
A cool image for a blog article on topic of "%post_title%" - this one is for "anime", "digital art" and "neon punk" presets.
The
Stability AI API is very cheap, like $10 for thousand of generated images.
P.S. That's for mainstream of course...