Not sure I understand the question. You would put the filespec between the quotes on the line:
$PictureBox1.Picture = "c:\winnt\sysvol\adioph\superman.bmp"

Now the path "c:\winnt\sysvol\adioph\superman.bmp" would only be available if the script is running on the domain controller where the file exists but I doubt that is where you want to run the script.
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