I don't understand WebImageView and WebPicture and Picture

If I drag a png file into my project
I have a webContainer and inside that container is a webImageView.
How do I set the WebImageView.Picture to actually display that picture?

When I drag the png into the project what is it? Is it a picture?

Yup. You can assign the picture to the webimageview by selecting it in the picture popup in the behaviour section.

I am referring to code.

UP_Picture As WebPicture
Down_Picture as WebPicture

Sub Constructor(up as Variant, down as Variant)
  // Calling the overridden superclass constructor.
  // Note that this may need modifications if there are multiple constructor choices.
  // Possible constructor calls:
  // Constructor() -- From WebControl
  // Constructor() -- From WebObject
  Down_Picture = down
  UP_Picture = up
  buttonImageView.Picture = UP_Picture
End Sub

This is displaying nothing.
I declared up and down as variants because I don’t know what I am passing to the method

folderButton = new WebDynaViewToggleButton(ClosePicture, OpenPicture)

ClosePicture and OpenPictures are the names of the png files I dragged into the project.