PIL saving corrupted images

Luciano Mollea <[email protected]> Sun, 3 Mar 2013 12:06:39 +0000 (GMT)
Newsgroups gmane.comp.python.image
Message-ID <[email protected]>
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I am trying to split an image into a number of same-sized chunks to use it =
as a base for a "Map Tile"/"Map Layer" web application.=0AThe image I have =
is a 30+MB BMP image (24 bit) about 3000x2500 sized.=0AThe mapping js libra=
ry i'm using (leaflet) wants a "tile server" with tiles of 256x256 and an a=
ppropriate naming scheme=0ASo I used PIL to write a simple python script to=
 create those tiles, cropping pieces from the original image.=0AIf I save t=
he tiles to BMP files, everything's fine. If I save them to PNG or JPEG the=
y are corrupted.=0A=0APNG files complaint that they are invalid files (usin=
g pngcheck it tells that the "image may have undergone a unix-dos conversio=
n").=0AIf I use JPG conversion, images are corrupted (I see images as a bun=
ch of 8x8 blocks with just noise instead of the expected image slice).=0A=
=0AI'm using PIL on Python 2.6.6 on windows 7 64 bit.=0A=0A(mind, I used PI=
L for another image manipulation script on the same machine and that script=
 works fine)=0A=0AAny hint about what could be wrong?=0A=0ATHanks=0A=0ALM
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<html><body><div style=3D"color:#000; background-color:#fff; font-family:ti=
mes new roman, new york, times, serif;font-size:12pt"><div>I am trying to s=
plit an image into a number of same-sized chunks to use it as a base for a =
"Map Tile"/"Map Layer" web application.</div><div>The image I have is a 30+=
MB BMP image (24 bit) about 3000x2500 sized.</div><div>The mapping js libra=
ry i'm using (leaflet) wants a "tile server" with tiles of 256x256 and an a=
ppropriate naming scheme</div><div>So I used PIL to write a simple python s=
cript to create those tiles, cropping pieces from the original image.</div>=
<div>If I save the tiles to BMP files, everything's fine. If I save them to=
 PNG or JPEG they are corrupted.</div><div><br></div><div style=3D"color: r=
gb(0, 0, 0); font-size: 16px; font-family: 'times new roman', 'new york', t=
imes, serif; background-color: transparent; font-style: normal;">PNG files =
complaint that they are invalid files (using pngcheck it tells that the
 "image may have undergone a unix-dos conversion").</div><div style=3D"colo=
r: rgb(0, 0, 0); font-size: 16px; font-family: 'times new roman', 'new york=
', times, serif; background-color: transparent; font-style: normal;">If I u=
se JPG conversion, images are corrupted (I see images as a bunch of 8x8 blo=
cks with just noise instead of the expected image slice).</div><div style=
=3D"color: rgb(0, 0, 0); font-size: 16px; font-family: 'times new roman', '=
new york', times, serif; background-color: transparent; font-style: normal;=
"><br></div><div style=3D"color: rgb(0, 0, 0); font-size: 16px; font-family=
: 'times new roman', 'new york', times, serif; background-color: transparen=
t; font-style: normal;">I'm using PIL on Python 2.6.6 on windows 7 64 bit.<=
/div><div style=3D"color: rgb(0, 0, 0); font-size: 16px; font-family: 'time=
s new roman', 'new york', times, serif; background-color: transparent; font=
-style: normal;"><br></div><div style=3D"color: rgb(0, 0, 0); font-size: 16=
px;
 font-family: 'times new roman', 'new york', times, serif; background-color=
: transparent; font-style: normal;">(mind, I used PIL for another image man=
ipulation script on the same machine and that script works fine)</div><div =
style=3D"color: rgb(0, 0, 0); font-size: 16px; font-family: 'times new roma=
n', 'new york', times, serif; background-color: transparent; font-style: no=
rmal;"><br></div><div style=3D"color: rgb(0, 0, 0); font-size: 16px; font-f=
amily: 'times new roman', 'new york', times, serif; background-color: trans=
parent; font-style: normal;">Any hint about what could be wrong?</div><div =
style=3D"color: rgb(0, 0, 0); font-size: 16px; font-family: 'times new roma=
n', 'new york', times, serif; background-color: transparent; font-style: no=
rmal;"><br></div><div style=3D"color: rgb(0, 0, 0); font-size: 16px; font-f=
amily: 'times new roman', 'new york', times, serif; background-color: trans=
parent; font-style: normal;">THanks</div><div style=3D"color: rgb(0, 0, 0);
 font-size: 16px; font-family: 'times new roman', 'new york', times, serif;=
 background-color: transparent; font-style: normal;"><br></div><div style=
=3D"color: rgb(0, 0, 0); font-size: 16px; font-family: 'times new roman', '=
new york', times, serif; background-color: transparent; font-style: normal;=
">LM</div></div></body></html>
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