How does 4chan alter the uploaded images?
For example, take this image here.
When I upload it to 4chan (just as I did now), 4chan changes the content. The filesize actually gets bigger and the MD5 checksum changes. So when I download it from 4chan it has a different content than the original one at http://i.imgbox.com/CYxDEuzl.jpg
Could the admin or some other knowledgeable person tell me the script (I guess it's some PHP routines) how the images are altered?
I think it just does stuff to prevent abuse or similar things. Like some pictures taken from digital cameras or phones have extra information in them and it strips it out.
There was also something about a bot that would upload malicious images telling people to rename them to ".hta" and run it, so I'd imagine when 4chan it resaves the image it gets rid of things like that.
>>546705
open with paint
save as 24-bit .bmp
rename rar
unzip
>>546705
Understandable. But I would like to know the exact changes/routines.
I've been able to get results consistent with what 4chan does with
jpegtran -copy none
I wish they'd stop doing it. It makes it harder to search for things by hash. Leave it enabled on /soc/ and maybe /b/ and a few others. There's certainly no reason to do it on the image dump boards, especially the cartoon ones.
>>547012
At this point, people are too stupid to not DOX them selves.
Just get out, it saves people from them selves.
>>547013
>people are going to dox themselves on /e/
>>547014
Yes.
I've seen people do it on just about any board I've been to.
What is geolocation data?
Filenames are even dangerous, these idiots post pictures directly from their facebook, with the original file names.
You can do facebook/middle number of pic
and get their real identity.
>>547015
Find me a single image on /e/ that might have contained personal info in the metadata had it not been stripped. Or /c/, /d/, /h/, or /aco/. How often is that going to happen, once a month? Then tell me why we should care. Nobody is scanning those boards looking for people to dox.
>>546949
Holy fuck!!! That seems to work!
