convert a PIL Image to a wx image

def PILTowx(pimg):
    '''convert a PIL Image to a wx image'''
    from MAVProxy.modules.lib.wx_loader import wx
    wimg = wx.EmptyImage(pimg.size[0], pimg.size[1])
    try:
        wimg.SetData(pimg.convert('RGB').tobytes())
    except NotImplementedError:
        # old, removed method:
        wimg.SetData(pimg.convert('RGB').tostring())
    return wimg