Security Issue - Posting Photos From GPS Enabled Devices

[Steve Herschbach]

A topic got brought up at http://www.detectorprospector.com/forum/topic/1510-awesome-day-in-the-desert-sw/?p=17706 which is so important I wanted to cover it in detail on it's own thread.

There is a feature in digital photography whereby information about the photo can be encoded directly into the photo itself. This originally was just information about the photo itself including the original file name and camera setting information, date taken, etc. There are two common formats you are likely to run into - EXIF and IPTC. EXIF tends to be technical details about the photo, and IPTC is more about copyright, description, and other details useful for publishing. Details on EXIF and IPTC here.

When cameras equipped with GPS became a possibility, GPS information was added to the EXIF data. This was normally just something common to phones with GPS built in but more cameras are now coming with GPS built in and more GPS units are coming with cameras built in. Activities like geotagging and such make tying location data to a photo very popular. All those photos loaded up for viewing in Google Earth? Way easier if the location data is encoded into the photo.

I use a great little free program called IrfanView which is amazingly powerful and compact. The IrfanView portable version can run off a USB stick. IrfanView has a photo information tab under Image in the menu which reveals all the EXIF and IPTC information, and allows the IPTC information to be modified. You can also set options for stripping EXIF data, both on image save or via batch processing. Like I said, very powerful little program.

When you display the EXIF information in IrfanView, it offers to display the photo location in Google Maps, Google Earth, and some other mapping programs. Great for photos you took but can't remember where.

OK, here is a photo I took on my phone, cropped, resized, modified the brightness, and added a caption. I saved as a renamed jpg but did not toggle the checkbox that strips EXIF data. I want to show that just because an image has been modified does not mean that data gets changed. Here is the image, and then a shot from IrfanView showing the EXIF data....

Now, you could save my lake image to your computer, and open it in IrfanView and view the EXIF data, but there is an easier way. Depending on your browser you need to get the address of the first photo I posted. If you use Chrome, just right click on the photo, and choose copy image address. Or you may have to click on the photo, choose the Save option, and copy the address out of the browser window. Bottom line depending on the browser you need to get the address where the image resides online. In this case the address for the lake image is http://www.detectorprospector.com/forum/uploads/monthly_01_2016/post-1-0-57762000-1451694506.jpg

If you have copied that address (again, easy way is with Chrome) now go to this website http://www.verexif.com/en/ and where it says Or paste a picture URL paste in the address of the photo and hit return. A page will pop up with the basic EXIF information, and you will see a map at the bottom of the page showing you where I took that photo!!!!

Notice the site has an option for stripping EXIF information from your own photos.

It gets better. If you have an iPhone or similarly equipped device it even knows the direction you are pointing the camera, and this data is also encoded. If you did download my photo and open it in IrfanView you can load the location directly to Google Earth and see where I was and which direction I was pointing the camera. In Google Earth below as loaded from IrfanView the view was looking straight to the top of the screen capture which is rather obvious since I was taking a photo of the lake. The funny part is I named the photo "looking west" and now that I see where I was and the direction of photo it was looking east.

OK, lessons learned. First, just use a camera without GPS, which is what I normally do. If you use a phone or other GPS enabled device, learn where to shut the EXIF GPS recording off or just turn off the GPS when taking photos. Even then I would use IrfanView to make sure you did it right. Possibly the most dangerous thing is uploading directly from a phone as it is too easy to forget and load up location data without thinking about it.

Many sites like this one resize large images and EXIF information may get stripped in the process. In fact it is easier to lose the information than retain it if you do much with the image. It is not always bad stuff to have and keeping it can be a good thing - I purposefully use EXIF and IPTC information to help insure that people copying my photos without permission might be caught using the encoded data. It really is only the GPS location data that can be a problem given the nature of prospecting. But never count on the data getting stripped by a website, be sure it is not there in the first place if you do not wish it to be.

We all really like photos, myself in particular, which is why I set this forum up with generous photo display options. I sure do not want to discourage people from posting photos - I want to encourage it. But do be careful when posting photos from a GPS enabled device to be sure you are not posting more information than you intended.

[mn90403]

Thanks Steve.  Another very informative post on your forum.

[Azavsfan]

Great stuff Steve. The time spent explaining this and providing the links/example is greatly appreciated. I tried out the site with one of the photos from the original thread and there is no data there. I also tried the original image saved to my pc prior to forum upload and the only info was the resolution. Once you start pulling the thread on items it is amazing at the ways "big data" collects info. Thanks again for the site.

[chickenminer]

Excellent information Steve !  Shame on me, I always thought changing an original file would strip the EXIF data.

   I just learned an important lesson!  THANKS

[Sourdough Scott]

I've heard, all digital photos taken. Have GPS coordinates imprinted in every photo. They are imprinted in the pixels. They can blow up the photo and see the coordinates. So gov't agency's (FBI, CIA, KGB ( Klunkers Global Brutality) can use this to help in their case. Just something I heard, not sure if true or not.

[Steve Herschbach]

Scott, they can't imprint GPS data without a GPS. Just take photos with a device that has no GPS if you are worried about it.

[Sourdough Scott]

Steve, just something I heard. I have no issues with taking a photo with taking GPS on or off.

[Trent King]

If you take photos from your iphone/ipad you can use this app

https://itunes.apple.com/au/app/photo-investigator-view-edit/id571574618?mt=8

Just click the photo then click remove data.

[matt]

Dang Steve, I was going to guess that you were on North Lake Blvd East of Fabian Way just past the 7-eleven to take that picture. My in-laws have a house on the lake just below your picture spot. Not to mention the street was named after my Grandfather. I have spent a lot of time there!

You can see Cal Neva Casino across the bay.