python PIL bug: 'NoneType' object has no attribute 'bands' (解決)

我有如下一段代碼，用於做tumbnail,

    mode = image.mode
    if mode not in ('L','RGB'):
        if mode == 'RGBA':
            alpha = image.split()[3]
            bgmask = alpha.point(lambda x:255-x)
            image = image.convert('RGB')
            image.paste((255,255,255),None,bgmask)
        else:
            image = image.convert('RGB')

當遇到圖片mode 是 RGBA時，就會報錯：

 'NoneType' object has no attribute 'bands'

上網一查，才知道是pil的一個bug。解決方法很好辦：

vim /usr/local/lib/python2.7/dist-packages/PIL/Image.py

定位到1501 行
1494     def split(self):
1495         "Split image into bands"
1496 
14971498         if self.im.bands == 1:
1499             ims = [self.copy()]
1500         else:
1501             self.load()
1502             ims = [] 
1503             for i in range(self.im.bands):
1504                 ims.append(self._new(self.im.getband(i)))
1505         return tuple(ims)

1494     def split(self):
1495         "Split image into bands"
1496 
1497         self.load()
1498         if self.im.bands == 1:
1499             ims = [self.copy()]
1500         else:
1501             #self.load()
1502             ims = [] 
1503             for i in range(self.im.bands):
1504                 ims.append(self._new(self.im.getband(i)))
1505         return tuple(ims)

這樣子就可以解決掉這個bug了。