已安装libjpeg，安装PIL时也显示

--- TKINTER support available

--- JPEG support available

--- ZLIB (PNG/ZIP) support available

--- FREETYPE2 support available

*** LITTLECMS support not available

但是在使用的时候依旧报错

File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/PIL/Image.py", line 1559, in thumbnail
self.load()
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/PIL/ImageFile.py", line 189, in load
d = Image._getdecoder(self.mode, d, a, self.decoderconfig)
File "/Library/Frameworks/Python.framework/Versions/2.7/lib/python2.7/site-packages/PIL/Image.py", line 385, in _getdecoder
raise IOError("decoder %s not available" % decoder_name)
IOError: decoder jpeg not available