Comments on: Awesome Web App for Photo Forensics

By: miklos

miklos — Sun, 07 Feb 2010 20:14:28 +0000

Perfect! Thank you.

By: Michael Zhang

Michael Zhang — Sun, 07 Feb 2010 11:55:26 +0000

Thanks for the comment and the clarification :-)

By: chromoose

chromoose — Sun, 07 Feb 2010 11:02:11 +0000

Miklos : you're exactly right - it takes your 70% quality images, and resaves them at 95%, so essentially, 67%. There is not much difference between 67% and 70%, so it won't show much.

The way this tool can be used to check for manipulations is if there are differing error levels throughout sections in the image. If everything is pretty uniform throughout, (even if it is bright) then it's an indication that is has not been manipulated.

I put an faq on my site if you'd like further clarification: http://www.errorlevelanalysis.com/faq/

By: chromoose

chromoose — Sun, 07 Feb 2010 10:58:21 +0000

Hi there,

I'm the author of that website - in order to address some of the questions raised here, I've put up an faq: you can see it over it http://www.errorlevelanalysis.com/faq/

By: Happy_Tinfoil_Cat

Happy_Tinfoil_Cat — Sun, 07 Feb 2010 09:43:47 +0000

FYI, all except the dog pic were heavily edited. In some cases, absurdly edited.

By: miklos

miklos — Sat, 06 Feb 2010 07:42:39 +0000

I usually save my shots for web, (http://www.miklos.ca) at about 70% to minimize filesize... So if what this process does is resaves the image at an even lower percentage, say 95%, wouldn't it just be saving 95% of 70%? My "straight out of camera" shots saved for web are showing huge errors. This thing is dumb :)

By: Jason Black

Jason Black — Sat, 06 Feb 2010 05:43:31 +0000

Disappointing. First link is original, totally untouched other than cropping and resizing it so I could upload:
http://errorlevelanalysis.com/permalink/c5dee29/

This link is an edit I did where I artificially blurred the background and edited out the baloon's string:
http://errorlevelanalysis.com/permalink/8c2c5c5/

The first one (the original) indicates far more editing, and the string edits don't show at all in the edited one (in fact the original shows the string as possibly being edited in!).

Interesting idea, though.

By: Michael Zhang

Michael Zhang — Sat, 06 Feb 2010 05:16:45 +0000

This article has a couple interesting examples, though they don't deal with subtle changes:

http://www.wired.com/threatlevel/2007/08/resear...

Here is the same image run through the app: http://errorlevelanalysis.com/permalink/5dfa1d3/

By: Happy_Tinfoil_Cat

Happy_Tinfoil_Cat — Sat, 06 Feb 2010 00:17:41 +0000

By: TomK32

TomK32 — Sat, 06 Feb 2010 00:03:44 +0000

Scans of analogue shots, not modified if I remember correctly

http://errorlevelanalysis.com/permalink/86ea601/
http://errorlevelanalysis.com/permalink/2d6a20f/

I guess resizing is doing it's part as well.