http://www.photo.net/bboard/q-and-a-fetch-msg?msg_id=003j8d


We would like to alert our users to a problem caused for Web browsers
and other applications by certain JPEG files created with Photoshop 7. 


With PS 7, Adobe decided by default to embed XML-encoded "preview" data
into JPEG files, using a feature of the JPEG format that permits
embedding of arbitrarily-named "profiles". In theory, these files are
valid according to the JPEG specifications. However they break many
applications, including Quark and, significantly, various versions of
Internet Explorer on various platforms. 


The symptom in Internet Explorer is that the browser becomes "stuck" in
downloading an image file, and its memory utilization starts to increase
at the rate of about 100K per minute. After this occurs, the browser can
still navigate, but it will not display any images at all -- neither
offending PS 7 JPEG images nor any other kind of images, on photo.net or
any other site. People have noticed this behaviour and tend to blame it
on photo.net, since they don't encounter it on other sites. This is only
because other sites have more control over the images that are included
on the site, whereas photo.net currently accepts all JPEG files. 


Once the browser is blasted by one of these JPEG image bombs, one can
recover on some platforms by closing all browser windows and restarting
the browser. On some platforms, it is reported that it is necessary to
reboot the entire system. 


We have searched the Microsoft web site for Internet Explorer
workarounds or patches for this problem, and we have not been able to
find any. IE 5 and 6 on Windows 2K, and IE 6 on Windows XP are some of
the version/platform combinations that are impacted, but there are
likely others. 


On Adobe's web site, various workarounds given include using the "Save
for Web..." function to write the JPEG file, or to set Preferences to
disable the saving of "preview" data in output files. Since these
workarounds require action on the part of the Photoshop 7 user,
photo.net is currently at the mercy of any PS 7 user who does not know
about this problem or ignores it. 


We are therefore working urgently on a way to filter out these JPEG
images. In the meanwhile, we appeal to our users not to upload JPEG
images created in PS7 unless they have been saved using the "Save for
Web..." feature. 

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