[Image-SIG] Problem with optimize flag and GIF encoder

[Fredrik Lundh]

Hmm.  PIL doesn't officially support "optimize" for GIF files:

    http://effbot.org/imagingbook/format-gif.htm

so maybe this is some partially implemented feature that's been hiding
in there for ages.  I'm not sure GIF is such a great format for
thumbnails anyway; maybe the toolkit should be tweaked to render any
8-bit thumbnail as PNG instead?

</F>

On Sat, Nov 28, 2009 at 5:44 AM, Ian Ward <ian at excess.org> wrote:
> Hello,
>
> I am running python 2.5 and PIL 1.1.6 on Debian Lenny, and I've found
> that using the optimize flag when creating GIF files can create invalid
> images.  An example:
>
>>>> im = Image.new('RGB', (20,44))
>>>> im.save('test.gif', optimize=True)
>>>> im2 = Image.open('test.gif')
> Traceback (most recent call last):
>  File "<stdin>", line 1, in <module>
>  File "/usr/lib/python2.5/site-packages/PIL/Image.py", line 1917, in open
>    raise IOError("cannot identify image file")
> IOError: cannot identify image file
>>>>
>
> I came across this problem using django-filebrowser, which has
> optimize=True as a default for creating thumbnails of all image formats.
>
> Ian
>
> (sorry if this message gets posted twice, I'm resending 20h after my
> first attempt)
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