How do I use Gemini

I set up an API in Google's AI Studio with billing enabled. I set the image model setting to google/gemini-2.5-flash-image (I tried multiple models). I keep getting the same error. What am I missing?

models/google/gemini-2.5-flash-image is not found for API version v1beta, or is not supported for predict. Call ListModels to see the list of available models and their supported methods. 