Problem using GD library ImageJPEG function

[André Gasser]

hello newsgroup,

I just discovered a weird effect in my php code. here is the flow of my
code:
1. upload jepg file to server
2. create new (empty) jpeg file using imagecreatefromjpeg() function
3. use imagecopyresampled to resize src image and store in newly created
image from step 2.
4. use imagejpeg to get new jpeg data
5. store that data in the mysql database

NOW: when i use imagejpeg using 100% image quality, some images in the
database are corrupt, but NOT ALL only some of them.

when i reduce image quality to 60% i had no problem using a picture
which hat problem with 100%. images are ok this way.

does this have some logical explanation? is this a bug in the gd or
something?

I use PHP 5.0.2, GD bundled (2.0.28 compatible), and mysql 4.x

I will analyze that code in more detail...
thanx !
andré

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[André Gasser]

André Gasser schrieb:

hello newsgroup,

I just discovered a weird effect in my php code. here is the flow of my
code:
1. upload jepg file to server
2. create new (empty) jpeg file using imagecreatefromjpeg() function
3. use imagecopyresampled to resize src image and store in newly created
image from step 2.
4. use imagejpeg to get new jpeg data
5. store that data in the mysql database

NOW: when i use imagejpeg using 100% image quality, some images in the
database are corrupt, but NOT ALL only some of them.

when i reduce image quality to 60% i had no problem using a picture
which hat problem with 100%. images are ok this way.

does this have some logical explanation? is this a bug in the gd or
something?

I use PHP 5.0.2, GD bundled (2.0.28 compatible), and mysql 4.x

I will analyze that code in more detail...
thanx !
andré

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WOW!

Images become good if I use the call:

imageinterlace($myimage, true);

the doc says, that in this way, a progressive jpeg is created.

they even get good if I use a quality of 100%!!

very strange......

can someone explain this behaviour to me? thx! :-)

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