Image Optimization usage

Hi,

I’m using the Next.js Image component for optimizing local images only (no remote).
When looking at the Vercel usage tab I can see which projects are using how many “Source Image Optimizations” are happening per project.

Something I couldn’t quite understand from the documentation is if this is a recurring thing or a one time thing?

In my recent usage I saw that one of my projects used 200 optimizations when I didn’t deploy anything new. Why would this be the case?

Thank you for clarifying this,
Timo