Image alt text updates (#2442)

* Update identity.md

* Update new-field.md

* Update new-field.md

aspnetcore/security/authentication/identity.md

@@ -28,7 +28,7 @@ In this topic, you'll learn how to use ASP.NET Core Identity to add functionalit
 
     In Visual Studio, select **File** -> **New** -> **Project**. Then, select the **ASP.NET Web Application** from the **New Project** dialog box. Continue by selecting an ASP.NET Core **Web Application** with **Individual User Accounts** as the authentication method.
  
-    ![image](identity/_static/01-mvc.png)
+    ![New Project dialog](identity/_static/01-mvc.png)
  
     The created project contains the `Microsoft.AspNetCore.Identity.EntityFrameworkCore` package, which will persist the identity data and schema to SQL Server using [Entity Framework Core](https://docs.efproject.net).
  
@@ -51,7 +51,7 @@ In this topic, you'll learn how to use ASP.NET Core Identity to add functionalit
  
     Launch the application from Visual Studio (**Debug** -> **Start Debugging**) and then click on the **Register** link in the browser to create a user. The following image shows the Register page which collects the user name and password.
  
-    ![image](identity/_static/02-reg.png)
+    ![Register page with user input fields for Email (Username), Password, and Confirm Password](identity/_static/02-reg.png)
  
     When the user clicks the **Register** link, the `UserManager` and `SignInManager` services are injected into the Controller:
  
@@ -107,13 +107,13 @@ In this topic, you'll learn how to use ASP.NET Core Identity to add functionalit
     
     Next, right-click the **dbo.AspNetUsers** table and select **View Data** to see the properties of the user you created.
     
-    ![image](identity/_static/04-db.png)
+    ![Contextual menu on AspNetUsers database table](identity/_static/04-db.png)
 
 ## Identity Components
 
 The primary reference assembly for the identity system is `Microsoft.AspNetCore.Identity`. This package contains the core set of interfaces for ASP.NET Core Identity.
 
-![image](identity/_static/05-dependencies.png)
+![Project references of ASP.NET Core Identity](identity/_static/05-dependencies.png)
 
 These dependencies are needed to use the identity system in ASP.NET Core applications:
 

aspnetcore/tutorials/first-mvc-app/new-field.md

@@ -42,11 +42,11 @@ Edit the */Views/Movies/Index.cshtml* file and add a `Rating` field:
 
 Update the */Views/Movies/Create.cshtml* with a `Rating` field. You can copy/paste the previous "form group" and let intelliSense help you update the fields. IntelliSense works with [Tag Helpers](../../mvc/views/tag-helpers/intro.md).
 
-![image](new-field/_static/cr.png)
+![The developer has typed the letter R for the attribute value of asp-for in the second label element of the view. An Intellisense contextual menu has appeared showing the available fields, including Rating, which is highlighted in the list automatically. When the developer clicks the field or presses Enter on the keyboard, the value will be set to Rating.](new-field/_static/cr.png)
 
 The app won't work until we update the DB to include the new field. If you run it now, you'll get the following `SqlException`:
 
-![image](new-field/_static/se.png)
+![Browser window showing an Internal Server Error: Sql Exception: Invalid column name Rating. There are pending model changes for Application DB Context. Scaffold a new migration for these changes and apply them to the database from the command line: dotnet ef migrations add (migration name) or dotnet ef database update.](new-field/_static/se.png)
 
 You're seeing this error because the updated Movie model class is different than the schema of the Movie table of the existing database. (There's no Rating column in the database table.)