RAM filling when changing views

Question

I accidentally found a problem in my application. I am using a template MVVM. If I start switching between views RAM starts fill up and dont free up.

Before https://i.stack.imgur.com/MBxG7.jpg

After 1 munute of simply views changing https://i.stack.imgur.com/fKh0t.jpg

I really dont know how find there is the problem. I will give you as much information as you need

I initialize all of views in MainWindowViewModel(it init first when app starts)

  private static ViewModel1 VM1;
  private static ViewModel2 VM2;

public MainWindowViewModel()
{
   VM1 = VM1?? new ViewModel1();
   VM2 = VM2?? new ViewModel2();
}

To get instance of any view I user this

  public static ViewMidel1 GetVM1()
  {
      if (VM1 == null)
          VM1 = new ViewMidel1();
      return VM1 ;
  }

In other view

ViewMidel1 vm = MainWindowViewMidel.GetVM1();

All views are UserControls. When view changed all view get properties triggered.

Maybe i do something wrong?

Constructors of views calls only when programm starts.

Diagsession https://gofile.io/?c=pamZlT

UPDATE 1:

I delete all code from all VM and its dont help. Something wrong with xaml. https://i.stack.imgur.com/YcqSZ.jpg

UPDATE 2: This xaml add ~15-20 mb in RAM every time I select view. Image size 108kb

<Ellipse Grid.Column="1" Grid.Row="2" Grid.ColumnSpan="2" Grid.RowSpan="2" Margin="5,5,5,5">
    <Ellipse.Fill>
        <ImageBrush ImageSource="/Resources/Images/image.jpg"  Stretch="UniformToFill"/>
    </Ellipse.Fill>
</Ellipse>