Clear a PictureBox

I have a picture box that has different images inserted when a combobox selection is made. I also have a clear button that clears all the contents on my form. How do I clear a picturebox? I have tried the following and none of them work:

picFrom.Image = vbNullString
picFrom.Image = ""
picFrom.Clear ()

Any ideas? I am sure this is an easy one I just seem to have hit a wall...

Thanks!

VB Code:

picFrom.Image = Nothing

See, I knew it was easy! Please pardon my ignorance...