[Image-SIG] Error when saving JPEG with quality above 85 and optimize
nirs at freeshell.org
Sun Apr 2 17:38:01 CEST 2006
When I try to save JPEG files with quality above 85 and optimize=1, I
get this traceback:
>>> image.save("foo.jpg", quality=86, optimize=1)
Suspension not allowed here
Traceback (most recent call last):
File "<stdin>", line 2, in ?
File "<stdin>", line 2, in save
File "/opt/local/lib/python2.4/site-packages/PIL/Image.py", line
1305, in save
save_handler(self, fp, filename)
line 409, in _save
ImageFile._save(im, fp, [("jpeg", (0,0)+im.size, 0, rawmode)])
File "/opt/local/lib/python2.4/site-packages/PIL/ImageFile.py", line
491, in _save
raise IOError("encoder error %d when writing image file" % s)
IOError: encoder error -2 when writing image file
For publishing photographs in both full size and thumbnails, I find
quality level of 90-95 to give the best results. I hoped that optimize
would give even better results :-)
I compared PIL, GIMP and Photoshop output, seems that all give almost
identical results for the same output file size. PIL seems to give
little sharper results - maybe because I resized the images using
ANTIALIAS and both Photoshop and GIMP support only BICUBIC filter?
Last, a note about the docs:
"Keyword options can be used to provide additional instructions to the
writer. If a writer
doesn't recognise an option, it is silently ignored."
Thats evil - if an option is not recognized, it should raise.
"The available options are described later in this handbook."
Where is the link to the options? at least where is "later"?
More information about the Image-SIG