Posted by Jack Jackson on 06/25/05 18:41

Edward Vermillion wrote:
> Sorry to reply to this message but I wanted the OP to find it too...
>
> On Jun 23, 2005, at 9:42 AM, Jack Jackson wrote:
> [snip]
>
>> Through your help I was able to validate image files using
>> getimagesize() and have made a nice script to upload and rename images.
>
>
> [\snip]
>
> I've been meaning to post a reply to a problem I ran into a while back
> that included validating images with getimagesize(). I've seen a few
> posts from folks saying this is the way to go and just want to share my
> experiences.
>
> My original problem was that a script I had for batch generating
> thumbnails from uploaded images was running out of memory. With Richard
> Lynch's help I was able to track the problem to createimagefromjpeg()
> using an unholy amount of memory on one particular file, a file that had
> passed through getimagesize() with no problems.
> What I found was that if an image ( in this case a jpeg ) is corrupted,
> but just barely, getimagesize() will let it through. Just for the record
> I could open it up in Photoshop and that's how I discovered that it was
> corrupted, the last ten or fifteen rows on the image were gone.
> Photoshop showed an uncompressed file size of 11M for this image. But
> what I had to end up doing is setting my memory limit to 48M before
> createimagefromjpeg() could get enough memory to work with that it
> finally failed.
>
> Just a heads up to anyone that's using getimagesize() to verify an image
> before running it through createimagefromjpeg(), just because it passes
> getimagesize() doesn't necessarily mean it's a good image.
>
> Edward Vermillion
> evermillion@doggydoo.net
>
Thanks for telling me about that, Edward. I apprecate it. Actually in
this case I was using it only to verify that it was something like an
image to validate the file type before allowing it on the server. But
you raise a very good point and I appreciate it.

JJ

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