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I am trying to make a simple function in python that can take in a filepath and an outputfilepath, and then make a 64x64 thumbnail for the image found at filepath and save the thumbnail to outputfilepath. Here is my entire code:

def create_thumbnail2(filepath, outputpath):
    if not os.path.exists(filepath):
        print "Input file path for create_thumbnail doesn't exist. Returning None"
        return None

    try:
        size = 64, 64 #Will be making a 64x64 thumbnail                                                                                           
        im = Image.open(filepath)
        print "image successfully opened"
        im.thumbnail(size, Image.ANTIALIAS)
        print "made thumbnail"
        im.save(outputpath, "PNG") #Save image as a PNG                                                                                           
        return outputpath
    except IOError:
        print "I/O error"
        return None

print "TEST 1"
filep = "test_images/cat1.jpg"
print create_thumbnail2(filep, "test_images/cat1_thumbnail.png")

print "\nTEST 2"
filep = "test_images/cat2.jpg"
print create_thumbnail2(filep, "test_images/cat2_thumbnail.png")

The problem is that this code will work fine for some images, but will raise an IOError on the line where I call "im.thumbnail(size, Image.ANTIALIAS)". Here is the output of the above program.

TEST 1
image successfully opened
I/O error
None

TEST 2
image successfully opened
made thumbnail
test_images/cat2_thumbnail.png

You'll notice that in the first test, the an I/O Error is thrown after the image is opened but before a thumbnail is created. In the second test no error is thrown, and the thumbnail is actually successfully saved to the outputpath. No matter what order I call the two different tests in, or if I comment one out and run the other one alone, the result is always TEST 1 failing and TEST 2 succeeding. Both cat1.jpg and cat2.jpg seem to be valid JPEG images, I can't really find anything different between them besides the file names and the actual picture content.

In case anyone wants to try it with my images, I downloaded cat1 from here: http://dellone2one.com/wp-content/uploads/2009/11/angry_wet_cat.jpg

and I downloaded cat2 from here: http://cvcl.mit.edu/hybrid/cat2.jpg

EDITED TO ADD THE FULL TRACEBACK WITHOUT THE HANDLING: Here is the full traceback

Traceback (most recent call last):
  File "image_utils.py", line 75, in <module>
    print create_thumbnail2(filep, "test_images/cat1_thumbnail.png")
  File "image_utils.py", line 66, in create_thumbnail2
    im.thumbnail(size, Image.ANTIALIAS)
  File "/Users/dylan/arcode/python/arcode/PIL/Image.py", line 1559, in thumbnail
    self.load()
  File "/Users/dylan/arcode/python/arcode/PIL/ImageFile.py", line 189, in load
    d = Image._getdecoder(self.mode, d, a, self.decoderconfig)
  File "/Users/dylan/arcode/python/arcode/PIL/Image.py", line 385, in _getdecoder
    raise IOError("decoder %s not available" % decoder_name)
IOError: decoder jpeg not available
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1 回答 1

1

我的 PIL 安装也是如此。（PIL 1.1.7、Py 2.6、OSX 10.6）

编辑：啊 - 在不同的 OSX 机器上安装有效。我知道在 OSX 上构建带有 JPG 支持的 PIL 存在问题，但我不记得这两个安装的来源是什么，所以我不能告诉你如何修复它。

编辑 2：我最好的回忆是使用类似此处的说明构建 PIL产生了工作安装。构建和安装命令必须运行 sudo，并且必须手动修改 gcc 的三个调用以删除“-arch ppc”选项并重新运行。

这是构建 PIL的另一条途径。

于 2011-06-15T23:59:59.920 回答