[web2py] Field compute= and make thumbnail

[Pepe Araya]

Hello,

I have a table where only store images related to x Article. 

db_define_table('images',
      Field('original_image', 'upload'),
      Field('thumb_image', 'upload')

Is efficient even, possible to make  'thumb_image' Field a computed Field?
Something like:

      Field('thumb_image', 'upload', *compute*= lambda r:*make_thumb*(r, 
85))


def *make_thumb*(r, thumb_size):

    try:
        from PIL import Image
    except:
        raise ImportError, "Requires PIL installed in your system."


    size = (thumb_size, thumb_size)
    ....

Any help is welcome!

thanks!