Google Image Bot returns Miss status

Hello Cloudflare Community
I have been experimenting with your Service and I have purchased the PRO version, since your service is very good!
However, I am seeing a problem (which is surely a configuration error on my part), the following in the analytics:
My site consists of many Images, however the Cached percentage is only 35%.
In the last few days I have especially controlled the Googlebot-Image/1.0 and I don’t know if it was a coincidence, when I have activated some functions like MIRAGE and Polish then the bot has stopped happening so often, I have controlled more and the vast majority of the requests of the robot have been returned with MISS.
For you to see and see if they help me with the problem, the site is
For the moment I will deactivate the additional functions, until I see if they can help me, since I see large fluctuations in the SERPS.

Thanks in advance!