[Image-SIG] IndexError: string index out of range

[Alex Ethier]

Hi,

I'm having troubles processing a PNG image with PIL.

I'm getting this error:

Traceback (most recent call last):
  File "test-image.py", line 12, in <module>
    resized = image.resize((int(sizeX), int(sizeY)), iFilter)
  File "/Users/alex/Envs/image-lib/lib/python2.7/site-packages/PIL/Image.py", line 1290, in resize
    self.load()
  File "/Users/alex/Envs/image-lib/lib/python2.7/site-packages/PIL/ImageFile.py", line 198, in load
    s = read(self.decodermaxblock)
  File "/Users/alex/Envs/image-lib/lib/python2.7/site-packages/PIL/PngImagePlugin.py", line 394, in load_read
    cid, pos, len = self.png.read()
  File "/Users/alex/Envs/image-lib/lib/python2.7/site-packages/PIL/PngImagePlugin.py", line 99, in read
    len = i32(s)
  File "/Users/alex/Envs/image-lib/lib/python2.7/site-packages/PIL/PngImagePlugin.py", line 47, in i32
    return ord(c[3]) + (ord(c[2])<<8) + (ord(c[1])<<16) + (ord(c[0])<<24)
IndexError: string index out of range

If I add a print statement in the PngImagePlugin.py code to print len of c:

def i32(c):
    print len(c)
    return ord(c[3]) + (ord(c[2])<<8) + (ord(c[1])<<16) + (ord(c[0])<<24)


I can see the following when loading the image

...
8
8
8
8
8
8
8
8
8
0
Traceback (most recent call last):
  File "test-image.py", line 12, in <module>
    resized = image.resize((int(sizeX), int(sizeY)), iFilter)
  File "/Users/alex/Envs/image-lib/lib/python2.7/site-packages/PIL/Image.py", line 1290, in resize
    self.load()
  File "/Users/alex/Envs/image-lib/lib/python2.7/site-packages/PIL/ImageFile.py", line 198, in load
    s = read(self.decodermaxblock)
  File "/Users/alex/Envs/image-lib/lib/python2.7/site-packages/PIL/PngImagePlugin.py", line 394, in load_read
    cid, pos, len = self.png.read()
  File "/Users/alex/Envs/image-lib/lib/python2.7/site-packages/PIL/PngImagePlugin.py", line 99, in read
    len = i32(s)
  File "/Users/alex/Envs/image-lib/lib/python2.7/site-packages/PIL/PngImagePlugin.py", line 47, in i32
    return ord(c[3]) + (ord(c[2])<<8) + (ord(c[1])<<16) + (ord(c[0])<<24)
IndexError: string index out of range

I'm assuming that the image is "broken" and therefore pil can't load it.  but I can load the image in photoshop and preview on the mac.
Any idea of what I can do to fix this problem?

Thanks.
A