[kovidgoyal]

from calibre.ptempfile import TemporaryDirectory

with TemporaryDirectory('xxx') as tdir:
   for x in ('one.jpg', 'two.jpg'):
      with open(os.path.join(tdir, x) as f:
         f.write(get_resources('images/' + x))
    about.exec_()

It is important to note that you should exec your dialog inside the outermost with block as the temp dir will be deleted when you exit the with block.