OT: ImageInfo or some other tool to detect Animated Gifs.

[Scott Silva]

Duncan, Brian M. spake the following on 10/17/2006 8:17 AM:
> I know it's off topic, with all the Fuzzy OCR talk and ImageInfo talk I
> figured someone might know.
> 
> Any way to specifically detect an animated GIF?  Now we are getting
> (very few but I am sure it will increase) these animated GIF pump and
> dump Spams that Fuzzy OCR cannot process succesfully.  I will paste one
> in here, I hope this message is not caught as Spam.  I am not sure if
> it's the OCR engine or the way the animate GIF is designed.
> 
> As you see it slowly scrolls through the text included in the image,
> then if you wait long enough (like 10 minutes) the final frames of this
> animated GIF are only the background with NO text.
> 
> Based on what Fuzzy OCR is telling me the only text it sees is some /
> and \.  (Which happen to be what is left on the final frames of this GIF)
> 
> If I could just add a score for ANY included animated gif I highly doubt
> I would have any false positives.
> 
> Thanks for any info.
> 
I looked at about a dozen animated GIFs and I see one common thing. They have
the text string "NETSCAPE2.0" (without the quotes).
You would have to add something to the magic that the file command uses(mine
is /usr/share/magic), and then you could ban that filetype in MailScanner.
I would check as many animated GIF's as you can before you try this to make
sure that string is there.
I don't see that string in my magic file, so it shouldn't conflict with
anything, but I can't be sure about false positives.

Or you could just ban all gif images, if that will fly with your users.




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