[MarkMc]

The presence or absence of an image depends on user votes. If you feel an image is not useful, click the '...' button and select 'Suggest or Choose an Image' > 'This story does not need an image'

[rkagerer]

Is there a way I can raise the threshold?

Not every story is deserving of a photo, and if their presence felt more curated it might significantly improve my experience on your site.