Curious... why strip EXIF from attachments but embrace it in the gallery?
- Thread starter Kevin
- Start date
Nicky Vermeersch
Active member
From a privacy viewpoint, it makes sense having exif data since photos are meant to be shared in the media gallery, where the EXIF date might be useful. But when using it on the forums where its usually shared with a different goal, it sounds logically to me to strip the exif data?
Kevin
Well-known member
Not really since the gallery offers no way of disabling the EXIF or, at the least, removing the GPS tags. Typical image sharing sites like Flickr offer user options to control their EXIF data. Vice versa, there is no way of not stripping the data from attachments.
Seems more of a product marketing point than anything.
Most files you download from most websites on the internet have EXIF stripped, so makes sense it would be stripped from attachments uploaded to the forum as well.
I think the reason it's enabled in Media is because most forums are for hobbyists around a particular topic and I think there is overlap between hobbyists in one domain with people who are into photography, where the EXIF data is interesting to other photographers (camera type and settings, etc.).
I think the reason it's enabled in Media is because most forums are for hobbyists around a particular topic and I think there is overlap between hobbyists in one domain with people who are into photography, where the EXIF data is interesting to other photographers (camera type and settings, etc.).
Kevin
Well-known member
The curiosity at hand is not what the sections of XF might be used for but rather that it is inconsistent to force two opposing ideologies in the same software. In one section of XF user EXIF is forced to be stripped out regardless of whether you want it to be or not while another part of XF forces you to share EXIF whether you want it to be or not.
I don't believe we explicitly strip EXIF data in most cases (though I'd have to double check). If you upload a small image as an attachment and re-download it, it'll likely still have the EXIF data in it. If you upload an image that gets resized, that's a different story, but the data isn't maintained by GD. I believe Imagick can retain it, though I think we do strip it there -- that's more for a consistent output, though additionally EXIF data can take up a significant amount of space depending on what exactly is in it (like embedded thumbnails). Percentage-wise, on a small image, this is much more significant.
Equally, I don't think that stripping EXIF data and displaying a subset are inherently at odds. There are some EXIF details that can leak things that people might not realize, like GPS coordinates. Conversely, an aperture or shutter speed doesn't reveal any personal information.
Equally, I don't think that stripping EXIF data and displaying a subset are inherently at odds. There are some EXIF details that can leak things that people might not realize, like GPS coordinates. Conversely, an aperture or shutter speed doesn't reveal any personal information.
RobinHood
Well-known member
I think stripping at the minimum, the location data is probably the safest default behaviour, for privacy reasons. Or stripping it from the image itself, even if it’s stored elsewhere in the database.
The ability to (optionally) save gallery media with location data, or manually override it, can be pretty useful though.
With @sonnb’s gallery you can browse a map and view photos by location, which can be great for events or venues where lots of users are uploading media taken at the same location.
However this should probably be an optional feature that requires actioned user consent when uploading, as if it’s defaulted to on then it can unknowingly expose the users home addresses, in some cases this is incredibly accurately.
The ability to (optionally) save gallery media with location data, or manually override it, can be pretty useful though.
With @sonnb’s gallery you can browse a map and view photos by location, which can be great for events or venues where lots of users are uploading media taken at the same location.
However this should probably be an optional feature that requires actioned user consent when uploading, as if it’s defaulted to on then it can unknowingly expose the users home addresses, in some cases this is incredibly accurately.
Attachments
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In XFMG you can decide yourself which EXIF data you show and which not. Geo location data should not be shown without a clear reason and a clear warning to your users.
It is a large security risk if you allow EXIF location data to stay in pictures uploaded to your forum posts. Many people are not aware that this allows everyone to find out where exactly they live, work, etc. I can't believe that XenForo still does not strip the location data out of forum attachments.
For XF1, we use this add-on to protect our users:
xenforo.com
It is a large security risk if you allow EXIF location data to stay in pictures uploaded to your forum posts. Many people are not aware that this allows everyone to find out where exactly they live, work, etc. I can't believe that XenForo still does not strip the location data out of forum attachments.
For XF1, we use this add-on to protect our users:
[WMTech] Exif Location Data Remover
Description: Exif Data Remover is an essential tool for professional XenForo boards to protect their users. Nowadays with GPS connected smartphones used to shoot photos, most pictures include hidden meta data (called "Exif" for "Exchangeable...
xenforo.com
Kevin
Well-known member
With XFMG that personal info' like GPS coordinate are still in the image, just not being shown in the GUI. The image that is presented in the browser can be easily scanned for the GPS info. Besides GPS info there isn't much else in there that might be considered personal but some people might be auto-populating the Artist and/or Copyright values with their real names without realizing it (depending on their setup).
You're right about the embedded thumbnails, something more common then some may realize, and you've put something else on my "To Do" list.
Interesting, can that remove just the GPS meta tag group or does it remove all EXIF (and just EXIF or all meta tags)? Ideally, for any site dealing with photography, uploaded images, whether in the forums or XFMG, would allow the retention of meta tags while selectively stripping some. I don't think selectively stripping tags will ever become an XF item because it really isn't that easy to do with straight PHP (unless a 3rd party library like ExifTool is incorporated) but it'd still be nice if admins had a choice in whether it should be stripped or not so we can, at the very least, be able to tell users "Yes, your data is stripped." or "No, your data isn't stripped, be cautious." instead of "Well, if you upload the photo in this spot your data is stripped but if you upload the exact same photo to this other spot then your data isn't stripped so be cautious here but not there."
Right, but I believe that is the case with attachments too, if they don't get touched by the image processing systems. Most noticeably this would be for resizing an image to fit, though we do also rotate images based on EXIF details. I was mostly trying to respond to your initial position, though it wasn't 100% clear what you were referring to. I presumed you were referring to the EXIF details that XFMG picks out and displays and I see no issue displaying that even if we chose to aggressively strip EXIF data in the future.
For reference, I have just exported a photo of mine from Lightroom and uploaded it to my local install. After downloading, I can still see the EXIF data -- it's the same bytes that I originally uploaded. I reduced my attachment dimensions such that it was then resized and the data was stripped. This is consistent with what I was saying. The EXIF stripping is more incidental based on some environmental settings and you may be seeing different behavior because you aren't necessarily hitting dimension limits in the MG. There may be a difference in behavior, but your messages make it seem like we're actively stripping EXIF in posts and not in the gallery.
I vaguely thought there was an open suggesting about stripping EXIF data from uploads, though the only suggestion I found actually related to maintaining it through image processor actions (presumably most specifically because of things like copyright).
Kevin
Well-known member
But XF is actively stripping EXIF posts and not in gallery, with a "*" footnote of "Based on settings", and it is out of our control (the stripping, not the settings). It'd be far more consistent if admins were able to control to either strip or not strip at a higher level then having to rely upon file size/dimensions & what part of XF something is uploaded to.
Note that this is more of a frustration borne out of spending some time digging through the topic in general as part prepping a 2.1.x migration for a 1.x add-on heavy reliant site.
nocte
Well-known member
I think it would be really necessary to add an option to remove EXIF data, so I created a suggestion:
xenforo.com
Add option to remove EXIF data from images/attachments (such as GPS data)
There should be an option to remove EXIF data from images. Leaving things like GPS data can be a serious privacy issue: Many people won't realize that this data is added to their photos and may expose more than they want. There is an addon from @wmtech that does this for XF1, but has no XF2...
xenforo.com
Kevin
Well-known member
Just be careful of what you ask for, that add-on seems the remove all data, not just GPS.
MySiteGuy
Well-known member
Author and copyright tags, for instance, that someone may want to keep in their images.
eva2000
Well-known member
Yes that. Imagine if folks upload images with geotags which they forget are embedded and upload photos revealing their locations which they didn't intend to.
Scandal
Well-known member
Hello guys!
Recently I received some complaints from my forum members that the EXIF data (more specifically the GPS coordinates) are appearing on their uploaded images. For this reason, I developed a small addon to prevent it.
You can find it here:
xenforo.com
Recently I received some complaints from my forum members that the EXIF data (more specifically the GPS coordinates) are appearing on their uploaded images. For this reason, I developed a small addon to prevent it.
You can find it here:
Beta - Strip JPG Attachments EXIF Data
This addon strips/ removes inline any jpg/jpeg exif data uploaded via your Attachments and Media Gallery system. It keeps only the icc so as to not affect the display of the image. This can protect your member's sensitive data like GPS...
xenforo.com