I have noticed the same thing. At the moment I am converting a PIL image to a ui.Image using the following code (where img is the PIL image)
imgfile = StringIO.StringIO() img.save(imgfile, format='PNG') imagestring = imgfile.getvalue() ui_image = ui.Image.from_data(imagestring)This is the best method I have found in the beta, but unfortunately I don't think there are any built-in functions to do it for you.