Override method in PictureService from a plugin

Hi
I want to override a couple of methods in the PictureService. I want to do it in a plugin.
So I added DependencyRegistrar in my plugin like so:

 public class DependencyRegistrar : IDependencyRegistrar
    {
        public virtual void Register(ContainerBuilder builder, ITypeFinder typeFinder)
        {
            builder.RegisterType<Nop.Plugin.Misc.ImageNew.Services.PictureService>().As<IPictureService>().InstancePerHttpRequest();
        }

        public int Order
        {
            get { return 10; }
        }
    }

Now in my class Nop.Plugin.Misc.ImageNew.Services.PictureService I don't want to implement all the methods of IPictureService.  I want to implement only 2 of them and use all the old methods from the original PictureService.

How can this be done?
Thank you for your answers.
Lev

Simply inherit your Nop.Plugin.Misc.ImageNew.Services.PictureService from default Nop.Services.Media.PictureController and override required methods

Thank you it worked