Is it posible to every time I create a Product its MUST have a assets (Mandatory), like a picture?
You can hook into catalog events.
In theory this should work
var contenEventHandler = EPiServer.ServiceLocation.ServiceLocator.Current.GetInstance<EPiServer.Core.IContentEvents>();
contenEventHandler.SavingContent += contenEventHandler_SavingContent;
void contenEventHandler_SavingContent(object sender, ContentEventArgs e)
//your conditions and actions
e.CancelAction = true;
The idea is to prevent saving a product and show the client a error msg if the assets list is empty, or some other condition in assets.
I will try the eventHandler...