[gentoo-user] {OT} image metadata and privacy

[gentoo-user] {OT} image metadata and privacy

[Grant]

Has anyone found a way to completely sanitize images of all
potentially privacy-invading metadata for posting online?  I recently
discovered that there is actually an EXIF thumbnail image.  So if you
have a photo and you crop it and post it online, the EXIF thumbnail of
the original uncropped image is still there for all to see.

- Grant

Re: [gentoo-user] {OT} image metadata and privacy

[Daniel Frey]

Hi Grant,

Yes, I just had to do this myself.

There are two packages: jhead and exiftool. The former does jpegs only.
I wound up using exiftool, there's a single command to strip all metadata:

exiftool -all= *.jpg

If I remember right that creates a copy of the file it processes.

You can use exiftool to list tags and also remove individual tags. I
used it to make sure there were no GPS tags in pictures from my phone.

Dan

On 09/05/2013 06:32 AM, Grant wrote:
> Has anyone found a way to completely sanitize images of all
> potentially privacy-invading metadata for posting online?  I recently
> discovered that there is actually an EXIF thumbnail image.  So if you
> have a photo and you crop it and post it online, the EXIF thumbnail of
> the original uncropped image is still there for all to see.
> 
> - Grant
> 

Re: [gentoo-user] {OT} image metadata and privacy

[Grant]

> Yes, I just had to do this myself.
>
> There are two packages: jhead and exiftool. The former does jpegs only.
> I wound up using exiftool, there's a single command to strip all metadata:
>
> exiftool -all= *.jpg
>
> If I remember right that creates a copy of the file it processes.
>
> You can use exiftool to list tags and also remove individual tags. I
> used it to make sure there were no GPS tags in pictures from my phone.

I thought I had some problems getting exiftool to work with a PNG file
but now I realize I didn't understand how to use it.  I think that
should be the de facto method for removing EXIF data from many
different image formats.

- Grant


>> Has anyone found a way to completely sanitize images of all
>> potentially privacy-invading metadata for posting online?  I recently
>> discovered that there is actually an EXIF thumbnail image.  So if you
>> have a photo and you crop it and post it online, the EXIF thumbnail of
>> the original uncropped image is still there for all to see.
>>
>> - Grant

Re: [gentoo-user] {OT} image metadata and privacy

[thegeezer]

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On 09/05/2013 02:32 PM, Grant wrote:
> Has anyone found a way to completely sanitize images of all
> potentially privacy-invading metadata for posting online?  I recently
> discovered that there is actually an EXIF thumbnail image.  So if you
> have a photo and you crop it and post it online, the EXIF thumbnail of
> the original uncropped image is still there for all to see.
>
> - Grant
>
http://stackoverflow.com/questions/13646028/how-to-remove-exif-from-a-jpg-without-losing-image-quality/17516878#17516878



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Re: [gentoo-user] {OT} image metadata and privacy

[Paul Hartman]

On Thu, Sep 5, 2013 at 8:32 AM, Grant <emailgrant@gmail.com> wrote:
> Has anyone found a way to completely sanitize images of all
> potentially privacy-invading metadata for posting online?  I recently
> discovered that there is actually an EXIF thumbnail image.  So if you
> have a photo and you crop it and post it online, the EXIF thumbnail of
> the original uncropped image is still there for all to see.

Whether or not the thumbnail remains uncropped depends on the cropping
software. Competent software should not do that to you, but as we know
not all software has been created equal.

You can use jpegoptim --strip-all to remove any and all extra data
from your picture. Gentoo package name is media-gfx/jpegoptim.