If I see AI imagery on your thumbnail/blog post/display pic/advert/website it sends a loud and clear message that this is a super low-effort operation and I shouldn't assign any value to it.
non-model-generated non-clip-art image options I have used:
- a relevant or amusing photo from my own library
- a hand-coded design via Processing / Pillow / ImageMagick / etc
- a visualization of data referenced or processed in the post
- a relevant screenshot (for code or software posts)
- a color or gradient block
- paid art (if you have an idea, cheap commissions are out there)
- and of course evaluating whether the post actually is improved by an image