Will generating SAS URLs for multiple images on each request significantly impact performance, especially when the product list is large?
I have not heard that this would be an issue, because SAS generation is done by your server. However, this is something that you should be able to test somewhat easily if your server is affected by this.
Does frequent SAS URL generation result in increased costs, especially with a large number of requests?
Storage cost isn't affected by this.
What’s the most efficient and secure way to manage this process? Couple of points:
However, I would also consider using Microsoft Entra ID authentication if that is possible in your case. Also, one option is to pipe the images trough the App Service (or whatever you are using here) and handle the authentication and authorization there.