.NET Images do not support PSD file directly, so there is no way to "persuade" a PictureBox to show a PSD file, without handling it's Paint event and readign teh file and drawing it's content yourself.
That's a lot of work, but these may help for starters:
Reading Adobe Photoshop images[
^]
Yet Another PSD Parser[
^]
They are both quite old though, and you will have to modify them to support the latest PSD file format(s) - they change and evolve over time, as new versions of Photoshop are released.