How to store images generated by my application into the cloud Azure or AWS without to use a SQL database ?
You need to use the API from the cloud service. Take a look: https://docs.microsoft.com/en-us/rest/api/
For AWS, you can use S3, their storage service. You can use either the Mobile SDK for .NET & Xamarin or an API to send files.
I believe the Azure equivalent is Azure Storage.
Xamarin Inc., as a wholly-owned Microsoft subsidiary acting as a separate legal entity, adheres to the Microsoft Privacy Statement: Privacy & cookies