AttributeRouting in ASP.NET Web API for Hypermedia Web APIs. Links user user/picture (It's a child resource)

gistfile1.cs

RoutePrefix("user")]
public class UserController : ApiController
{
    public UserController()
    {
     
    }

    [GET("", RouteName="GetUser")]
    public UserProfile Get()
    {
        ...

        var resource = new UserProfile
        {
            Email = user.Email
        };

        resource.Links.Add(new Link
        {
            Rel = "picture",
            Href = this.Url.Link("GetUserPicture", new {})
        });

        resource.Links.Add(new Link
        {
            Rel = "myexercises",
            Href = this.Url.Link("GetMyExercises", new { date = "?"})
        });

        return resource;
    }

    [GET("picture", RouteName = "GetUserPicture")]
    public async Task<HttpResponseMessage> GetPicture()
    {
        ...
    }
}