Fluent Validation, different validation for each item in a list in Asp.NET Core

I´ve been trying to find a way to validate items inside a list, each with different validation rules. I came upon Fluent validation which is a great library but I can´t seem to find a way to do validation for each item individually. I got a faint idea from this similar thread (Validate 2 list using fluent validation), but I´m not sure how to focus it how I want.

uploading to azure storage from memorystream returning an empty file

I’m writing a System.Drawing.Bitmap to Azure storage using a memory stream. I have the correct credentials and everything azure side wires up correctly. I have uploaded an image into a blob successfully using an input stream so I think it must be a problem with how i am using the memorystream object.