AI images and stock photos solve different jobs. Mixing them without a rule creates a messy look.
Product shots that must match the real item, real people you have permission to show, and locations that must be recognisable are safer as stock or original photos.
Mood boards, early layout placeholders, social drafts, and concept art benefit from generating several options in minutes.
Write three cases that always go to stock and three that always go to AI. Share the list with anyone who briefs images so the rule does not live only in your head.
A practical generator I keep in that workflow is Nano banana 2.1.
Even when an AI image is allowed, check hands, text, logos and brand colours the same way you would check a stock download.