Hi Sam,
See if this is helpful:
import clr
clr.AddReference("Eto")
clr.AddReference("Rhino.UI")
from Rhino.UI import *
from Eto.Forms import *
from Eto.Drawing import *
dialog = Dialog()
dialog.Title = "Sample Eto Dialog"
dialog.Padding = Padding(5)
image_view = ImageView()
image_view.Image = Bitmap('C:\Users\Dale\Desktop\Test.png')
dialog.Content = image_view
dialog.ShowModal(RhinoEtoApp.MainWindow)
– Dale